Gwen: from Lance Corporal to Warrant Officer at Bletchley Park

I have said that I was rather overawed by the Oxonians in our small ATS group, so it might have been expected that I would be overwhelmed by the brilliance and eccentricity of the denizens of Bletchley Park itself. But not so: we were very much the newest intake and a pretty lowly rank, so we only came into touch with the next echelon above us individually and about twice a day. They would descend on us from what we called the Fuzz Room (Fusion) and we would tell them what we had found out. One of our number, Anne, did come into contact with quite a lot of people in the ad hoc games of mixed hockey played on an empty bit of the Park, but as an Oxford Blue she terrified both teams by her speed and ferocity. However, culturally speaking, my horizons were very much extended. There were musical concerts in the Assembly Hall by professionals from both outside and inside the Park, and I would go up to London with an increasing number of friends, sometimes taking in a matinee or a concert and staying overnight with their families. Their lifestyle was different from what mine had been. It was no surprise to me that they ate dinner at night, preceded by drinks, but it was extraordinary to find that the hyper-intellectual parents of some girls lived in large but very dusty houses with dangerously toppling piles of books even on the staircase.

Professionally my first job was to deal with the networks serving the northernmost Army Group on the German eastern front. For the first few days I gave complicated reasons for everything I found out. But after this, Wallace Farmery, on his visitations from above, would say 'Just give me the results'. So I did. I was never any good at understanding the order of battle of our own organization and I certainly didn't understand that at Bletchley at the time, but I suppose that the Fusion Room was acting as a channel between the Log Readers and the Decrypting Sections and the Intercept Station Controllers and the Indexers and whomever else needed to know what we might have found out.

After this I was moved to deal with the communications of the German Police. These were unusual nets, three in number, two controlled from Berlin with a number of outstations, but they all used fixed call-signs and they were all working on long range frequencies. It was quite easy to sort out the two top level networks, but which of them was ordinary police, military police or Gestapo, I don't know to this day and I wouldn't have asked, and if I had, I would have been told there was no need to know. This was an absolutely rock solid principle, until I got into the Fish Section late in 1943. The two major police networks were separated in frequencies by about 5kc/s, but the third network, which produced three times as many logs in a day, was on 410kc/s and consisted of all the outstations on the two upper nets and all their out-stations, all transmitting on the same frequency. This sounds impossible, but it's due to the vagaries of the atmosphere that fairly high-powered transmissions on long wave will reach a certain radius via the ground wave. So the controls of each subnet could get in touch with all their outstations but not interfere with those in geographically adjacent areas. But the atmospheric wave bounced back in such a way that all the stations on the net were heard all at once from the distance of the UK, so the intercept stations had great difficulty in sorting out which control, which subnet on this 'everything together' net was contacting which outstation. So you had to resolve a number of Morse corruptions in order to get them fitted in properly. This I managed to do, apparently to the satisfaction of the visitor from the Fuzz Room, who in this case was a wonderfully turned out young captain by the name of Raymond Lisser. Raymond had, in Joyce Grenfell's phrase, 'a lovely polish on his shoes and his hair'.

Then I moved in the summer of '43 to my first command. By this time I was a sergeant, having taken Senior Commander Pat Baber's hint that I must get my hair cut, because I would never be made a sergeant, unless I did. The army in the West Section consisted of me in control, a couple of WAAF corporals, an ATS subaltern, a British Army regimental sergeant major, who was by far the most intelligent of the lot, and an American captain, of whom I can only say that he was a very good tennis player. That was quite interesting. I don't quite know how much I contributed, but Senior Commander Haber would come round and collect things every day and seemed quite impressed. I was giving what I knew (well - suspected) to be re-encodings and corrections to messages where they were indicated by the chatter and so forth.

Then in late summer 1943 Yvonne Buckoke, who became my friend for life, had just been moved to her single command (having already been commissioned) which was to try to do traffic analysis on the High Command printer links known as Fish. These were quite difficult and the army corporal who had been in charge before had stated that you could not possibly discover anything from their radio links, because, to start with, they worked without call-signs and each end worked on a different frequency. So you had the difficulty of fitting two ends together before you started to log it in any sense. But Yvonne saw a chink of light and hauled me in to help, and within no time at all we had about 14 ATS and a gentle, charming but slightly dazed man called David Rex Uzielli, who was in nominal charge. Here we really came into contact with both the intercept station, which was Knockholt in Kent, and with the cryptography people divided into two sections called the Newmanry and the Testery, each breaking one half of the cipher, or trying to, one under Max Newman and the other under Ralph Tester. Now, we only saw Max Newman once in our office, as far as my memory goes. He usually sent a captain, Peter Marshall, to speak to us. The people in the Testery we knew very well and they used to come and have coffee with us in the mornings and eat the Naafi cake, which was bright yellow from the dried egg and was reputed to be mixed with castor oil. We also went to visit them in their room in the next corridor in F Block (which is now razed to the ground) and there we found people like, or not like, because they were so individual, a very smart captain called Roy Jenkins, whom everyone will have heard of, Peter Hilton, who became a distinguished maths professor in the USA after the war, and possibly the richest soldier in the British Army, Peter Solomon Benenson. He had refused a commission and was drawing the much greater pay, in effect, of a regimental sergeant major, but was once put on a charge for failing to turn up at a pay parade. He later became the founder of Amnesty International.      There were also a couple of people from the British Museum, one of whom, when on holiday, sent us postcards in the most beautiful italic handwriting in a style which resembled that of 'Finnigan's Wake'. The other, who was just a corporal, whom we called by some fish name or other, Chad I think, turned out, I found out by an obituary years later, to have been a very important member of the British Museum staff. There was also a very bright army captain who had been a journalist on the Daily Mail and the Times. There was also Angus Mackintosh, a tall major with black hair and green eyes who in Oxford later lectured in Old English and held a room full of students enthralled by delivering Wulfstan's Address to the English given at the beginning of 1000 AD, lambasting them for evil behaviour and saying they would be deprived of beautiful things: 'mondes-licht ond regen-scur'- moonlight and showers of rain.

The Fish nets added to the difficulties of traffic analysis by using a Q-code all of their own, except for some very well known Q signals referring to whether the interference they were finding was natural or man-made. And one of my first jobs was to sort it out. Late in the war we captured a whole lot of documents related to Fish. In fact Yvonne and I went to a prisoner of war camp somewhere, where a whole caravan with its mobile crew of two Germans was there with all its machinery and codebooks. So that was extremely interesting. Yvonne did speak German, being half Swiss, but we had with us I think Captain Fletcher, who was a very good German speaker, so Yvonne and I kept quiet, while he tried to get some information out of these two chaps. By this time it was obvious to us that they were reading the ciphers on various of these links, indeed on most of them, but it was never directly acknowledged, although it was clear that we could (from those supposedly unrevealing logs) get information, which could help them in various ways. We were also able to help the intercept station, and in the early summer of 1944 1 was sent to Knockholt, the intercept station, nominally to reorganize the traffic analysis section there, but actually to try to pick out from my knowledge of how things happened, the messages which should most urgently be teleprintered to Bletchley, which would lead them into the day's keys. I didn't know that — it was obviously a decision made high up by those who knew that D-Day was fast approaching.

Before I went to Knockholt, I was told that I was to wear civilian clothes, since it was a civilian station, but I said that the only civilian clothes that I had which I could get into was my school uniform. As a special concession I was allowed to go in uniform as a staff sergeant. I was driven down by a Colonel Sayer, actually in a Jaguar! Then I met the traffic analysis section, about six or seven young local housewives or schoolgirls under a rather grande dame, who had been in Room 40 during the First World War and had no idea how to deal with these youngsters. Also neither she nor the girls ever really ventured into the set room. The set room was manned by people invalided out of the Merchant Navy and the only woman who was in there quite often was a Scots girl called Netta Eddington, who was a very good technician, called in when anything went wrong with the machinery. I knew her later and that, not only was she a very good technician, but she was also a very good cook. I remember her giving a splendid Burns Night dinner with haggis and all the trimmings, washed down with some very good whisky. I came to know what were called the Charge Hands, who were in charge of each shift, of whom there were four. One I can't remember much about at all, one was called Alan Clark and used to play tennis with the girls in the traffic analysis section, but he died young. The other two were Stan Silsby, who ended up in charge of Gilnahirk intercept station, and Jock Harkins, who moved to Somerset when Knockholt was moved entirely, and finished up his career as commander of the big station in Scarborough, where I met him years later and we had dinner together.

After I had been at Knockholt for about a fortnight, I was woken in my billet by a blaze of light in a room which had no lighting and no black-out curtains. The light was from searchlights endlessly criss-crossing the sky and was accompanied by the noise of all the ack-ack guns in Kent. I only found out the next day at Knockholt that this was the beginning of the doodle-bug (V1) attack. We soon learned to take no notice, because either the thing was going to cut out and drop on you or continue droning on its horrid way.

So much for my professional career, as it were, up to the time when I went back to Bletchley park and was made a company sergeant-major. The insignia for a CSM was a sort of squashed circle attached to your tunic on the forearm, instead of stripes on your upper arm, which led to a misunderstanding on a night train to Scotland, where I was going for a 48 hour leave on a farm which belonged to some family friends. I had been chatting with quite a few soldiers in the train—everyone in trains talked to each other as they do in Italy today. Anyway, when we had to change trains at Carlisle and left the dim blue light of the carriages for the stronger lights of the station, a corporal I had been talking to said 'Blimey, I thought you was a cook'. Cooks wore an unsquashed circle in the same place as my insignia.

So far I haven't said much about life outside Bletchley Park. For the first few months the ATS were billeted in a dusty old house in Fenny Stratford and had to walk about half a mile or more at the beginning and end of each shift. I can't remember much about it, except that we had orderlies who swept and dusted and cooked for us, and so on. In our spare time we would go out and have a drink in a pub or go to the splendid Salvation Army canteen, where occasionally you could get chocolate off ration. I also got chocolate off ration, because I didn't smoke at the time, so I would swap my cigarette allowance with those who didn't want their chocolate, which worked very well. One night a gang of us went to the local cinema which was showing a film called 'Blood and Sand' – a kind of modernised Beau Geste. We were convulsed with laughter and were making what we thought were witty comments. The manager asked us to leave.

After a few months we moved into the newly built Shenley Road military camp, where all the army and ATS employed at the Park were billeted, and it was back to huts, but thank goodness no bunks and no earwigs. They were, however, rather Jerry-built and in the sergeants' hut where I was sleeping, one night the whole roof blew off and after a few moments a sleepy and grumpy Elizabeth asked "Who opened that window?'' We had to walk through the muddy roads to get to the ablutions block, to wash ourselves and our clothes, though mostly I took them home and let my mother do them on my day off once a week or once a fortnight.  And I would hitch up there with my friend Angie who lived close to Coventry. We would share the ride, mostly in lorry cabs, as far as her dropping off point and then I would get dropped off on the A5, which ran through Fenny Stratford and right up to within a mile of my own home. I went back to Bletchley by a train, which left Nuneaton at 8.22 pm and was supposed to get to Bletchley in about a couple of hours. But quite often in father and I waited for ages, drinking Horlicks in the station canteen, waiting and waiting because, before the passenger train could come through, the fish train from Stranraer to London had to go first. It was often very late, midnight maybe, before I was walking from Bletchley station up to the Shenley Road Camp.

The Shenley Road camp was commanded by Colonel Fillingham from the Durham Light Infantry and there were various stories about his exploits. He was extremely interested in education and indeed made a very good OC of the Formation college, where Yvonne and I went for the last month of our service, in early 1946. He persuaded one of his DLI sergeant majors to come to Shenley Road to what he described to him as a Special Unit. So the sergeant major thought he was coming to a commando unit or something of the sort and arrived full of hope, only to find that, when he organised an early morning run for the soldiers (not for us thank goodness) it resulted in the countryside being littered with gasping Intelligence Corps chaps with their hands on their knees and all muddy, which was a great disappointment of course.

The Colonel also had a habit of stopping people as they were going around the camp and asking them questions. He once asked Angie and me "Are you frightened at this camp?" We said "No, we aren't frightened at all". He was reputed to have asked one of the Pioneer Corps, who were doing the sort of slave jobs around the camp. "My man, where are the Aleutians?" The man had never heard of the Aleutians and said "Hut H4 Sir", which was their ablutions. The Colonel also gave a performance in front of the men's daily parade at about 8.30 am by making great digging motions and asked them what he was doing. Nobody piped up with the right answer. He yelled at them that it was obvious: he was burying Sir John Moore at Corunna.

Colonel Fillingham had organised the planting of a huge number of shrubs and small trees around the military camp, even though all the roads were just beaten earth and very muddy at that. But about a week after he had done all this, a great flock of sheep got in and ate most of the vegetation, so it was all a bit barren after that. But at least we were able to walk across the fields to a nearby pub, where we played darts and so forth or went for general country walks.

The women were under the administrative control of another senior commander, who was a great rival with Pat Haber in the Park. Pat would quite often get us out of what was called 'a barrack night', where we had to stand to our beds with all our kit laid out in a specified order and be inspected by this aristocratic senior commander But Pat would sign a little note to say we were operationally required to be on duty in the Park.

There was a little more military discipline, which we had rather got out of the way of. We had to do occasional route marches or had to march around the barracks square, but for us it was nothing like as difficult as it was for the men. The Senior Commander in the camp rebuked me on barrack night, because I had a corner bed and had put my barrack box, which contained all my belongings, across the corner of the hut, whereas it should, according to regulations, have been quite solidly fixed at the bottom of my bed. Senior Commander reminded me rather sharply that this was an Attery, not an artery. But a few weeks later she sent a message to say that she understood I was rather good at painting and drawing, so would I do some murals in the hut. So I was able to say No, I was much too busy with my work in the Park and I could not possibly be painting there, when I was working shifts at night, evening or day – a petty revenge.

I also quite deliberately risked being put on a charge when we were being marched around the camp, because I was in a blank file, which meant there were two blank spaces in the row of three I was marching in. I deliberately marched round a puddle and then I was able to say, 'Well, we are attached to the Intelligence Corps'. So that was that.

I should also say that, apart from showing confidence in that way, I had gained an enormous amount of confidence in the office. One night when I was on night duty all alone, I had just collected all the logs from the dispatch rider from Knockholt and was flicking through, when I suddenly saw something which interested me. Without a second's hesitation I lifted the phone and called the War Office and told the duty officer that Rommel was moving his HQ in France. They probably knew this already but they thanked me very kindly. That was something I would never have dared to do even a year before.

The next thing that happened to me professionally was that I was recommended for a commission and went off to a War Office Selection Board. But that was so extraordinary in itself, as was the rest of my service career, that I shall leave it for next time.

Gwen's Road to Bletchley Park

In December 2022 we said farewell to a 98 year old former colleague, Gwen Tovey who in 1942, while still Gwen Herbert, had begun a career in signals intelligence which lasted until she retired. Seven or eight years before she retired, she dictated her memories of her time at Bletchley and of the move of GCHQ to Cheltenham into a cassette recorder and these were transcribed by a friend. This transcription was spread across a number of separate pieces which were shared with retired and current members of GCHQ. At her funeral I asked members of her family and the friend who had transcribed them whether I could publish them here, and as everybody agreed, here is the first instalment.

Part One: "Why Me?"

The inhabitants of Bletchley Park were many and various, and so were the routes by which they got there - but I challenge any survivor to match the unlikelihood of my selection! The process which led to my first walk up the narrow. dark and sooty path from Bletchley station to the gates of the park and the suddenness of my encounter with a world which up to then had existed only in books were probably also rather unusual but utterly captivating.

In late 1941 I was in the third year Sixth Form of a small grammar school for girls in a town of some thirty thousand people, eight miles north of Coventry. My Head Mistress came home from some conference and said that the ATS proposed recruiting a dozen or so Oxford graduates for some unspecified special duties and there might conceivably be room for one or two school-leavers in the group. I had just spectacularly failed the entrance exam for Girton and had said that I was not going to try again in the middle of a war. So I said 'yes' to trying for one of these hypothetical places. I can't pretend that this was pure patriotism. It was a decision influenced by the bone-aching chill of two nights at Girton in November and by the humiliating realisation that it would be ridiculous to think that my languages were up to university standards. My German was almost entirely self-taught as the only staff member who could teach it succumbed to TB after two lessons. My written French was up to scholarship standard but speaking it was another matter. I had never even seen a foreigner until the War brought Poles to a nearby airfield (and the King's Own Scottish Borderers to the town, speaking an equally incomprehensible language). My ever resourceful Headmistress persuaded the Polish Meteorological Officer to give me practice in French conversation. I never told her, but the last thing Jerzy wanted to do was to talk French because, like many of his fellow officers, he had been badly treated in France; but he kept up the pretence because he liked using the school tennis courts and liked even more my mother's raspberry jam and sponge cakes. He wanted to talk (in English) about Shakspir and Sho (GBS of that Ilk). Jerzy went on to anglicise his name and to marry the daughter of a British Admiral and became Professor of Physics in a northern university.

So now imagine me in early 1942, possibly about to become a mole, aged 17¾, paralysingly shy, wearing a borrowed "grown up" hat, setting out for London where I had never been. I found my way to Devonshire House and was shown into a dusty room and asked to fill in forms. Under the heading "languages" I put down Modem English, Middle English on the strength of having "done" Chaucer's Prologue, French, Latin and elementary German. Then I was led into an interview room. The Chairman was a rather short and rather round Colonel. On his left was an ATS Senior Commander (Major) wearing as much make-up as a film star. The third member of the Board was a civilian from the British Museum named C. J. Gadd. (Some 55 years later when I became fascinated by ancient Sumerian history, I discovered he was famous for having recognised that a carved cylinder seal found in the city of Ur came from the Indus valley. This led to much work on the incredible amount of trade between the two civilisations between 2500 and 1900 BC.)

Most of the interview passed in a blur, but I clearly remember answering two questions in a way which could have led them to believe that I knew far too much about what I was being interviewed for and that it might be safer to have me inside, as it were. The first pivotal question was "what do you think you might do when you leave school?", and the second was "what would you call a circle turned inside out?" My totally innocent answers were, firstly, that I thought it would be interesting to be part of the BBC team which was monitoring German Public Radio broadcasts, though I feared my German was not good enough, and secondly, that if a circle were turned inside out its radii might look like a star. The answer caused a definite frisson because of course recruits would be studying German communications and the German names for military communications in the most used formats were Kreis and Stern - circle and star. I cannot think of any other reason why they should have chosen me, but after an agonising wait they said I had been accepted on condition that the ATS also considered me suitable.

That ends the first part of my saga. The next was bizarre but in a different way.

Part 2: "Basic Training" - for what?

After being accepted by the BP Selection Board I was given a date to attend an ATS recruitment centre. I cycled to Coventry, sailed through the medical but found the officers were distinctly miffed by the strict instructions they had received that on no account was I to be put through their trade aptitude tests. However, I passed muster, and two weeks after leaving school I proceeded to Talavera Barracks in Northampton, where we were doled out with approximately fitting and hideously unflattering uniform. My appearance was not improved when I washed my khaki stockings in Persil and they came out bright yellow. (I did once play Malvolio). We lived in one of the numerous wooden huts, each labelled "28 men - 8 horses". We slept on bunk beds on excruciatingly hard straw-filled palliasses. At night earwigs fell down on the unfortunate girl on the top layer and crawled down to the overheated recruit on the lower level.

The command "outside in threes" had us marching off to meals, P.T., route marches, lectures on hair nits and the Battle of Talavera, but most often to drill on the barracks square. There, in a blisteringly hot August, we marched about, exasperating the male Regimental Sergeant Major since half the company never learned which was their left leg. My worst experience was when, standing to attention, and having been told "do not blanketty blank dare to blink", I became squintingly aware that a large wasp was crawling up my plump cheek. The route marches affected many of the girls in my hut - a lot of them were conscripts from East London. After what seemed to me a gentle stroll, admittedly over some fairly hummocky fields, they returned exhausted and with badly blistered feet. Another trial was gas drill. The ATS sergeant had repeatedly instructed us what to do if there were a gas warning. She suddenly shouted "Gas" so we flung ourselves on the ground, wrenched off our caps and fumbled our gas masks out of their cardboard boxes, which we carried everywhere, and put them on. Sadly, a little white dog appeared and ran away with my cap. The squad was spluttering with laughter and so had to take off their gas masks. The sergeant, fearing she was losing control of the squad, was minded to put me on a charge until some bold soul pointed out that a prostrate girl in a gas mask could not possibly be capable of "Conduct prejudicial to good order and discipline".

We were not allowed out of camp without some very special reason so were able to save four weeks' pay which in total amounted to £2.

Thus ended my first encounter with the real ATS. Subsequently we were attached to the Intelligence Corps. The discipline they had tried to instil into us at Talavera was replaced by the discipline of the job we were doing and a determination to avoid as far as possible any interference with that job.

Part 3: Secret revealed

After our exertions in Northampton we were given a 48-hour leave before gathering at Beaumanor, the ancestral home of the Herrick family in Leicestershire. The Manor is surrounded by parkland and by 1942 this was planted with aerials and wooden huts. In the huts ATS girls laboured to transcribe the Morse code radio transmissions of German military units of all kinds. Reams of paper (which we called logs) were filled with messages and any intervening chatter. This was mainly in Q-code - for example QSA IMI means "what is my signal strength?". When we got to the park two of our group, both German linguists, were sent to join people attempting to decrypt the messages but most of us became "traffic analysts", following networks and stations as they changed frequencies and callsigns every day and trying to establish order of battle and to help cryptographers in various ways.

Many, many books, some good and some awful, have been written about techniques employed at Bletchley and at its outstations, but for any younger colleagues who want to learn about what it was like and how it fitted into the wider picture and its importance I would recommend two books by Michael Smith - "Station X", published in 1988 and "Secrets of Station X", published in 2001. The latter has more technical details but the former version has more about the atmosphere and the personalities. A remarkable evocation of Bletchley, both inside and outside the park, appears in Robert Harris's novel "Enigma" (comparable with his evocation of "Pompeii").

But before we knew anything of all this we were asked to sign the Official Secrets Act: anyone who felt they did not want to were to say so and would be released. It was now that we got to know the others in our group. I had already met, though only briefly, two other school-leavers who were friends from GPDST Sutton High School but Talavera had kept us pretty well restricted to our hut groups. There were eleven Oxford graduates and various life-long friendships began at this time. When we got into the classroom the next day we found an ATS subaltern, drafted in from who knows where (I suspect nepotism) and a whole group of soldiery who were destined for tactical units in the field.

The work was fascinating from day one to the penultimate day which we spent endeavouring to make sense of the great heaps of logs and reporting on our findings and then to the very last day when we were told that all had done well and all must have a prize of sewing a lance corporal's stripe onto our uniform because there were no Privates in the Intelligence Corps. (Some hardened battle-scarred fellows would say there were no soldiers either and that the rather attractive Tudor rose of the badge represents a pansy resting on its laurels).

We had some guest lecturers from BP but most of the instruction was done by Major Jolowicz, in civilian life the Professor of Law at Oxford. He was brilliant, not just in expounding technical matters and methods of attack, but also in somehow creating an atmosphere of hushed reverence. This was only broken once when an aircraft crashed into a hillside just beyond the manor and two Canadian soldiers were up and away out of the big bay window before Major J could thunder "Sit down".

The second of the resident lecturers (puzzlingly from a famous naval family) looked like a teddy bear in his khaki battle dress and was a man of great deliberation. He once drew a complex diagram on the blackboard in blue chalk, contemplated it in silence for a few moments, and then rubbed it out and did it all again in red.

There were snags in life, of course, not as far as the work was concerned but out of office hours. Moving from earwiggy huts to billets in substantial houses in the rural surroundings of the manor should have been pleasant, but unfortunately I didn't like either the girl I was billeted with or our landlady. Elizabeth was grumpy and sleepy, grumpy because I woke her every morning clattering about polishing my shoes and buttons while she wanted to sleep to the last minute. Our landlady was very nouvelle riche, always talking about her dead "hubby" who took her to Monte Carlo and gave her gifts of wonderful china - the hideous stuff was in glass cabinets all round the house, and I nearly crashed into one of them when I fell down the stairs one night on the way to the bathroom. The bathroom contained the only example I have seen of a shiny steel bath which acted as a distorting mirror when one sat in the regulation allowance of 2" of water. Every morning, once we were dressed, we had to slog the one and a half miles along the road and up the drive to the manor without even a cup of tea. Breakfast was taken in a beautifully panelled room and usually consisted of a sort of bright yellow pasty stuffed with some rather fusty prunes.

There was very little in the way of entertainment and at first I was rather shy of all these people who seemed so sophisticated. Their casual conversations were full of references to theatres, opera, art galleries, museums and foreign holidays. However, I soon began to enjoy trips on local buses to the only cinema in miles and an occasional fairly edible meal at a British Restaurant which cost 6 (old) pence. The chief pleasure for most of us came from walks in the countryside including field paths and going up and down the occasional craggy hill.

I quite often walked with a soldier who had been born in a high valley in Switzerland and then emigrated to some remote spot in the Canadian Rockies. Friedrich was intent on teaching me what he considered to be essential life skills. One of these, that of coming rapidly downhill without falling over, did come in useful in later Scottish holidays, though I never had occasion to test the rest of this lesson, which is that it is the only way to escape if you are being pursued by a bear. Nor did I ever find myself in the middle of nowhere in deep snow, and be thankful to know that by digging myself a deep hole I could survive the night. Friedrich also considered me dangerously innocent. One evening, having escorted me to the landlady's garden gate, he proceeded to teach me how to break the hold of a man attacking from behind. This was all in broad daylight and was witnessed by Mrs Whatever-Her-Name-Was, who wrote to my parents that she feared for my morals. This sent my mother into a fit but my father simply laughed because he had met Friedrich and Mrs X when he cycled over (petrol strictly for business) to bring me some apples from the garden. He knew perfectly well that any danger to my morals was, to say the least, unlikely. Disaster – potentially greater than that of any little white dog – was averted and I went on with full marks, unsullied name and a clear conscience to all the wonders of Bletchley Park.

I'll aim to put out the next instalment next week.

And There's More ...

It is hard for anybody whose experience of Sigint was of the Cold War or afterwards to realise how immature Traffic Analysis (TA) was at Bletchley Park as an analytical tool.  I am confident that this is another illustration of the point I made in my last post about TA against the Brown Network suffering because of a belief that any intelligence produced through cryptanalysis was necessarily more valuable than intelligence produced through plain text, or 'inference', as the product of TA was often described. 

The system used to express confidence in analytical results was straightforward: A% (reliable), B% (probable), C% (possible) and D% (what, before footballers' wives and girlfriends became an item of interest, might have been described as a WAG). A% was reserved for statements in plain language or decrypts, results which came verbatim from the horse's mouth. A result from TA, an 'inference', could never be rated higher than B%, because it hadn't been confirmed by an enemy source. It took  the Cold War, during which TA was the principal source of Sigint on the Soviet Armed Forces, for this almost theological insistence on TA's being secondary to cryptanalysis to disappear.

The reason for this is pretty clear: GC&CS was a cryptanalytical bureau between the wars, and for all that it developed into an intelligence organisation, its leadership was still mainly derived from cryptanalysts: after the January 1942 reorganisation for example, the Naval, Military and Air Sections were led by Birch, Tiltman and Cooper, while the important Huts (3, 4, 6, 7 and 8) were led by Jones, Birch, Welchman (later Milner-Barry), Freeborn and Turing (later Alexander). In their worldview, centralised TA existed to support cryptanalysis. GC&CS increasingly lost its ability to break military Enigma in the last year of the war, as German cryptography continued to improve:

"We now live precariously from week to week" (7 April 1945) and "A close finish is in prospect between the end of the war and the Hut 6 hold on the GAF” (14 April 1945) (both quotations in de Grey citing HW 77/6).

This shows the inability of the senior staff to understand that predictive intelligence of equal value to that produced by cryptanalysis was available from TA.

On the other side of the world, a Sigint organisation less encumbered by this single focus was demonstrating a different way of doing things. Central Bureau in Brisbane (CB) had little choice but to develop TA into a major intelligence source This wasn't just because of the difficulty of processing encrypted Japanese traffic, but because the shortage of intercept sets and operators and the difficulty in intercepting frontline transmissions which only used enough power to connect sender and receiver meant that CB had to focus on mainlines, and develop an understanding of Japanese military Orbat from the way messages were transmitted.

At the end of the war CB produced a technical report explaining what it had done, and how it did it, along with recommendations for doing something similar in the future if Australia needed to create such a structure in the future. (It can be downloaded from the National Archives of Australia: Series number B5436, Barcode 3207588.) Part H, which deals with Traffic Analysis at CB, describes the sort of mature TA recognisable to Sigint's Cold War warriors. It describes, for example, the preambles to Japanese military messages, and how they were interpreted; it explains the relay system which the Japanese had to use because of the immense range of their transmissions and the atmospheric problems which could complicate matter; and shows how communications structures reflected military structures, meaning that changes in comms structures presaged changes in military structures.

One section of Part H looks at TA inference methods, under thirteen headings: traffic volume; regular traffic associations; multi-addresses; redirected traffic; home depot connections; new locations and disappearance of old; general pattern and changes in nets; use of logs; use of technical features of messages; establishment of precedents; use of other forms of intelligence; co-ordination with Ultra; and co-ordination of methods. (I'm not going to copy out the whole of Part H here.)

Perhaps as important as the way in which communications security wasn't properly managed by Bletchley Park because there was nobody in the leadership to speak up for it, GC&CS's belief in the primacy of cryptanalysis for signals intelligence production, with only a handmaiden's role for TA, was a drag on the performance of the organisation as a whole, one that both limited the production of current intelligence and didn't promote an analytical mindset applicable to more than just one target.

Mistakes on Both Sides: Competing Ineptitudes

 

It is 59 years since David Irving's The Mare's Nest was published, and it is surprising that the massive release of records from the Second World War hasn't prompted a new look at the German development of cruise and ballistic missiles. My particular interest is, of course, the intelligence story: the way in which Sigint, Humint, Imint and Techint were fused to develop an understanding of what these weapons were and how – whether – they could be countered.

Perhaps it is the way in which the release of new records has added to the complexity which has led to its not being retold. Just one part of the Sigint story might serve to illustrate this. It is a story of gross German Air Force irresponsibility on the one hand, and of an almost wilful prejudice on the part of the authorities at Bletchley Park, and concerns the Traffic Analysis (TA) effort against the LN Versuchs Regiment, the Luftwaffe unit which carried out trials of new communications equipment. (This is a much abridged version of Section K of HW 43/82: The Sixta History, which was written by Mrs W E A Evans in April – May 1945.)

"The W/T picture of LN Versuchs Rgt was one of the first to be recognised as of the highest importance. As far back as 1940, when the number of Enigma keys was small, this network used its own key, E/Brown. Brown was broken in September 1940 and the decodes gave evidence of the Regt's unique position in the German Air Force (GAF) as the unit responsible for every kind of radio research and experiment. The devices developed were handed over to the different units of the GAF to use operationally, but generally there was a period when the staff of LN Versuchs Rgt were themselves concerned with operational working while they were training personnel of the regiments destined eventually to take over from them. Thus, not only did the activities of LN Versuchs Rgt provide an accurate forecast of the trend of radio development, so that what the Brown groups were playing with today would be a practicable device in serious use some six months later, but there were frequently times when the Regiment's networks were themselves used for operational traffic of the highest importance, during the earlier (and therefore more significant) periods of the employment of some new device.

Never was there a network with more need to be secure and with such a completely irresponsible attitude to security. Even the end-of-the-month report from each station saying that the prescribed security lectures had been attended by all personnel, gave such a reliable crib that it was a sure method of breaking the traffic of the last day of the month and at the beginning of the next mouth also, for some stations would certainly be late with their reports.

The trouble really came from the fact that this was the signals organisation of what was itself a signals regiment. Stations were small and Enigma traffic light so that frequently the man who sent the message had himself composed the text and encoded it. He therefore knew all about it and when the receiving operator was in difficulties would help him by giving him the internal indicator used, details of the key setting (including any mistakes which he might afterwards realise that he had made) and often the clear text of difficult parts, like the signature or outlandish placenames. More than that, if the accuracy of the text itself were queried he would come back in clear with an amplification of it or reasons why it must be right. The introduction of female operators in 1943 unexpectedly tightened security, as they didn't know the contents of the messages (though they were chatty on other topics). The exasperated male operator at the other end might then ask for one of his old buddies by name and if available the male operator would come to the set and chat usefully as usual.

One of the earliest examples of the value of these discussions of the contents of traffic was the case, on 26 May 1942, of the French outstation which took the Enigma message giving the early afternoon warning of what the target for his 'Ruffian' beams that night would be and came back to ask his control “3020 ODER 97?” It happened that this was the moment when control was introducing a new series of numbers for the British target-towns and has used “3020” instead of the usual “97” to indicate Southampton. (Unfortunately this was before Y stations were punctilious about submitting all plain language immediately by telephone or teleprinter and the logs were not seen till next morning, by which time Southampton had suffered. It was from this time that the organisation for reading Brown logs urgently was set up.

Usually, however, it was from operators' casual chat that odd bits of information of varying importance were obtained. Much, of course, merely had entertainment value, but a surprisingly high proportion of the gleanings were significant. One of the most straightforward of these was station identity established by operators 'signatures', usually three letters of the operator's name. At times it was the custom for operators to exchange signatures when they first came on duty and to take leave of their opposite numbers before going off. In this way a duty-roster could be compiled by the log reader with sufficient accuracy sometimes to predict days off. This may seem merely frivolous but it had definite uses, as another of the Brown habits was for the cipher clerk to use his own three-letter signature as an internal indicator. The usual practice was for two operators to be on duty together one sending and the other encoding. Hence, if on a particular morning two different signatures were recorded, the one sent less often would be that of the relief operator who was the cipher clerk and the indicator of traffic sent during the morning could be guessed. Similarly, if only one signature was intercepted, a study of the roster for the past few days would establish who was likely to be the other man on duty. Another use of station identity thus established was to suggest what officer's signature would be likely to be found in its traffic and provide a crib.

One of the more satisfactory episodes, when a significant development could be predicted by watching log signatures alone, occurred in the winter of 1941-2, when, after a period of inactivity on the French Group (concerned earlier with beam-bombing), the senior NCO at Control and at each of the outstations was noticeably absent during the early part of December. After 15 December, when the experimental group in NE Germany became active, each of these four men appeared at a different station on the new group, suggesting that they were there to try out refinements of their previous system rather than to learn something new, when they would surely all have appeared at control first. The tests continued until the beginning of March. A few days later the signature of the Chartres operator reappeared there, followed quickly by those of the other three at their old stations, the presumption being that the tests were satisfactory and the device perfected. A fortnight later the 'Baedecker' raids began, using an improved beam technique.

As time went on stations were recognisable from the subject matter or style of their chat, even if neither callsign nor signature were sent. This is where the importance of continuity of the log reading party became apparent. Often (especially after the arrival of female operators) there would be several pages of log consisting of nothing but an interchange of badinage, badly sent and corruptly intercepted, in a mixture of Q-code (often home-made), international 'amateur' procedure and abbreviated German, including of course slang terms. Occasionally a simple cipher would be included.

A story of useful gleanings from frivolous chat occurred on the Baltic Group in December 1943, when V1 plotting had been going on for three months with apparently good results. People were feeling a little edgy about when the flying bombs would be used operationally as the construction of sites in the Pas de Calais had been observed for some time but there was no indication of their being manned. For some days there had been odd scraps of chat between Control and an outstation about another man at control who came from the same home-town as the man at the outstation. They were hoping to meet when on leave, a sum of money being owed from one to the other. On 5 December the operator at Control said that the other man there proposed to give him the money under discussion, presumably because he would not now be meeting the outstation operator. The man at the outstation exclaimed:  "What! Is he not coming to France?" (note “coming”). Not at first, said Control, as he has to go on with the tests here till Christmas. Allowing for “embarkation” leave and a fortnight to install themselves (on the analogy of the earlier transfer to France, in 1943), Bomber Command began on the Pas de Calais on Christmas Eve, apparently, we are told, at the right moment.

These instances of insecurity were unauthorised – if operators had obeyed regulations nothing of the kind could have occurred. There were, however, several points at which the German organisation was itself insecure. Apart from the routine message mentioned at the beginning of this section, there was an involved routine of operational instructions when the French beam stations were to work, and a correspondingly simple routine message when they were not to work: “HEUTE KEIN EINSATZ” (No Deployment Today) followed by a signature.

There were few other routine messages, tuning messages being always nonsense. Cryptographic help was provided, however, by the fact that there was nearly always some station (sometimes several) without the current key and obliged to use an old one, so that messages would be re-encoded to suit. The detachment marooned on Bornholm and a party cut off by snow in the Tyrol (the courier killed by an avalanche) are obvious examples but there were many others, unaccountable sometimes but equally convenient.

The callsign system itself was insecure, in that, however involved the plan, there always was some kind of system and it never took very long to work it out, thereby giving away station identity. A habit of the comparatively inactive French stations in the late summer and autumn of 1942 gave information of a different kind. There was in existence then all along the Channel and Atlantic coasts, a system of warnings or signals indicating states of preparedness to meet invasion, either by sea or by air landings. These were indicated by “AX1“, “AX2” and “XS”, showing three degrees of intensity, and were repeated by wireless by French Brown outstations as an indication that they might have to go off the air and were therefore unwilling to get involved in traffic for the moment. They were sent with the time of the alarm and provided the British authorities with information as to whether a coast raid was expected or not, by checking the time given against the time when an alarm could have been given from normal observations. This was judged to be of such value that a system of telephoning the signal from the intercept station through GC&CS to the necessary British authority was instituted. The lines were not very straightforward, having to go through the Broadway exchange, but the record time achieved was nineteen minutes from the intercept set to the final destination.

Brown low-grade traffic was dealt with in its intimate relation to high-grade traffic and plain language, each illuminating the others. This gave the best possible results and no Section was heard to complain of the unorthodox arrangement. All agreed that it was the desirable plan to adopt for other groups with mixed traffic and lamented that it had not been found possible to reorganise Sections to that end. It must be emphasised, however, that the Brown plan only worked because the low-grade traffic was straight-forward enough to be dealt with by amateurs (though with enough intelligence background to know what to expect to find in the traffic). Whether this would have been the case in any circumstances, or whether small cipher experts would have been needed if more obscure codes had been used, cannot now be established.

Another point which contributed to the smooth working of the arrangement was that the codes were, in general, peculiar to this network, so that once their general working was understood it was not necessary to break every bit of the code in detail if sufficient intelligence was being gained in other ways. If the code had been useful in elucidating another, more obscure, network, more detailed work would have been essential and extra personnel with cryptographic experience needed. As it was, it would be truer to say that in most cases the Brown Party interpreted the low-grade traffic, rather than decoded it.

In fact, nothing substantial was added to intelligence by the breaking of Brown Enigma traffic after June 1942. Everything that was derived from source merely confirmed what had been established by low grade traffic and TA. This brings up a question of principle. It was only due to the accommodating practice of the Brown network in always passing a little Enigma traffic that the network was kept on priority cover. The messages about marriage leave for an Obergefreiter or a unit distribution of Christmas presents to married families providentially gave just enough Enigma traffic to provide a backing for the white lie that it was highly significant and needed the best possible cover. Of course, it was always potentially significant but in actual fact it never was (after 1942). For the last three years of the war it traded on the memory of the glorious Brown breaks of the Battle of Britain. Occasionally the Hut 3 intercept control section became restive and looked at the Brown material themselves but on the whole the bluff worked. When it failed, recourse had to be made to Black Market methods of obtaining sets, either at intercept stations not under Hut 3's control or by “under the counter” sets at the stations deputed to give Brown groups a limited amount of cover. Intelligence Control was always most sympathetic over this problem and did wonders while keeping within the strict letter of the law. The intercept stations themselves hated having to step down the priority of a Brown Group and did what they could. There were at least two moments of crisis when the Officers in charge of intercept stations themselves spent an afternoon logging Brown on their private sets, at their own suggestion. If it had not been for this co-operation the rules relating to cover would have resulted in the priority on Brown Groups being downgraded and the task given to less experienced operators and less suitable intercept stations. If the trivial Enigma traffic had been dispensed with altogether (as it well might have been, by the use of landline and courier) the Brown logs, if worth reading at all, would not have been read by a first-class log-reading party with access to technical and other sources of information. This brings up the whole question of the separation of intelligence derived from high and low-grade traffic.

It should be realised that to take only one example, all the information on the performance of V1 which was possessed by the Cabinet Committee on Flying Bombs before the operational launchings was derived from low-grade cipher and TA on the Baltic Group. The significant cover on this group was at intercept stations not controlled by Hut 3 and was obtained elsewhere through the Old Boy network. This is a disquieting thought."

The problem was that operational control of the tasking of intercept stations was dominated by cryptanalysts, and they suffered from the belief that material encrypted on high-grade systems was necessarily more sensitive (and therefore valuable) than material encrypted on low-grade systems, and that plain language material was equally necessarily less sensitive and less valuable. In another part of the forest, part of the success of Double Cross was due to amount of effort the Abwehr had to put in to derive intelligence from the reports of their "agents", and its consequent belief in its value. This is a perennial lesson for intelligence services: the ease or difficulty with which intelligence is acquired is not an indicator of its value.

The problem could be circumvented, because in a large and technologically complex organisation, senior staff tended to believe that their instructions would be carried out. The fact that OICs of interaction station kept a bit of resource spare, or that an analytical team, having learned that the system could not intercept the material it needed might contact those OICs to ask for some of that resource, would not occur to the senior staff managing the system. It also demonstrates that the "need to know" principle was managed rather more pragmatically than those at the top of the GC&CS structure might have believed: the OICs gave up resource because they understood what it might produce. (I don't imagine for a minute that this happens only in intelligence services.)

One final comment on German security, and one of the best Sigint insider jokes of the Second World War. The Q-codes used universally by radio operators were enlarged unofficially by Brown operators to meet their own needs. The most notorious instance of this was the introduction, after a security drive, of Q-signatures. Instead of the usual “OP?” enquiry for the name of the operator at the other end, the signal “QWA?” would be sent and the reply would be the letter Q followed by the first two letters of the operator's name, e.g. QHO for Hoffman, so that anyone monitoring would think he had misread a genuine Q-signal. The height of the fun was reached when the brothers Sauer were at different stations and would contact each other thus: -

“QSA ?”

“QSA 1 QSA ?”

“R.QSA 1. QSA 2”.

(Normally QSA means "what is the strength of my signals?" so the exchange looks completely authentic as an exchange of signal strength reports.

An Old Friend in Unfamiliar Company

 

If this blog has a tutelary deity, I suppose it is Frank Birch. He was Historian of Room 40 after the First World War, and, after being Head of the Naval Section (HNS) at Bletchley Park, became the Historian of British Sigint in the Second World War. He and I share the distinction of being the only in-house historians of British Sigint to have entries in the IMDB, though with 48 credits as an actor and one as a director, I think it is fair to say that his is a more prolific record than mine; and the IMDB doesn't record his successes on the inter-war stage, particularly his renowned Widow Twankey. He was a Fellow of King's College and a lecturer in history at Cambridge University, and sufficiently interested in racehorses to publish an account of racehorse pedigrees in 1926.

Penelope Knox is quoted in Birch's DNB entry describing him as a 'a many-sided human being—a rather dull historian, an acceptable drinking companion, a mysterious private personality, a brilliant talker and a born actor'. This is a very rare description of Birch as a rounded person. For Siginters, he is HNS and Head of the Historical Section, the man who didn't want 'Music While You Work' played in his building; for historians of the cinema, he is a bit-part player in a few dozen minor British films; for genealogists he is the husband of the Hon Vera Benedicta Gage, daughter of the fifth Viscount Gage.

So it comes as a major surprise to find him appearing in files released by MI5, and, what's more, not as just a name, but playing a minor part (ironically, just as in his film career) in the story of the Cambridge Five.  From interviews with Floral Solomon (KV 2/4634-5) MI5 learned that Birch had been living with Aileen Furse for a while before the war. On 4 September 1939, at Aileen's behest, Mrs Solomon invited Birch to a lunch she was hosting in order to introduce him to Kim Philby, who wanted to work in intelligence. (According to Mrs Solomon, Birch appeared to have been quite open about his work in Room 40.) At that point Philby was working for The Times. According to a 1971 summary of the Solomon case "Afterwards BIRCH saw PHILBY alone and thought him quite suitable for intelligence work but thought he had too good a job at the time for him to try to recruit him".

Was this a polite put-down? It's tempting to think that Birch would think that being a journalist was inferior to being an intelligence officer in GC&CS, but 'Times Correspondent with the BEF' was an impressive job description, and given that little relevant material was being produced at Bletchley at the start of the war, it may well be that Birch was giving an honest opinion.

What difference might it have made if Philby had, in fact, been recruited to Bletchley Park? My guess is very little: he would have learned little of any practical value to the Soviet Union – certainly no more than Cairncross got access to a couple of years later (as I recounted here), and like Cairncross, would have pressed for a move to London to get a job of more value to his controllers. Any competent Soviet Sigint official would have been able to infer British capabilities from the material it was producing, and a job in London where processed Sigint reporting was crossing his desk along with other intelligence material and assessment of its value would have been more valuable.

As for Birch: it looks as though nobody thought he was other than an innocent in this matter. Aileen left him for Philby, eventually becoming the second Mrs Philby and mother of his five children.

Another couple of GCHQ names appear in another of the recently released files. Before an interview with Lord and Lady Rothschild (reported in KV 2/4632) Peter Wright was asked to ask them about Gerry Morgan (who had been a member of the Cambridge University Socialist Society in the later twenties and early thirties) and Barbara Duckworth Maclean (who was a contemporary of Lady Rothschild at Newnham College, and had been on the 'Aid to Spain' Committee). They weren't known to the Rothschilds, and I imagine this was simply an attempt to check whether anybody who had been a bit pink at Cambridge might have developed into something more ideologically sinister.

With the exception of some of GCHQ's Directors and a very small number of Bletchley veterans, most of the hundred thousand or so British Siginters since 1914 are just names, possibly with a very small amount of information attached about where they worked. What really is strange is to meet them in such an unfamiliar context.

 

First World War Sigint Liaison with the Russians

I've written before about attempts to establish a Sigint liaison with the USSR during the Second World War. Less well known is the attempt to do something similar during the First World War.

On 25 August 1914, Captain Adrian Simpson of the Royal Engineers Signal Section (the predecessor of the Royal Signals) embarked for Petrograd on a mission to look at the improvement of wireless telegraphy links between the UK and Russia to better facilitate liaison between the two allies, each of whom was fighting the Germans and Austro-Hungarians on different fronts. Simpson spent the period October 1914 to the end on January 2015 on the front with the Russian Army and returned to Petrograd where he compiled a report for the War Office. His report contrasted the extremely high quality of the equipment the Russians had built or purchased with the very poor quality of the operators.  He had worked hard to improve matters himself: he had rebuilt the antenna system at the main Petrograd wireless station and boosted the power available to the transmitters but was nevertheless hampered overall by the operators, all civilian even on the front.

His report highlights the poor organisation of Russian military wireless telegraphy: the Military Technical School notionally managed the system, but in fact the ‘Société Russe’ (owned by the Marconi Company but wholly under Russian control) manned and ran it, but without an understanding of how the military communicated; non-operational messages were delayed for days at a time as a matter of routine, even when they were urgent indents for essential supplies; and little or no attempt was being made to intercept German cipher messages, never mind decrypt them: as soon as operators realised that the message they were copying wasn’t one of the Russian Army’s they stopped copying it; worst of all was their poor security: they used the same callsigns and frequencies, and transmitted their messages en clair.

Simpson discussed all of these matters with the Russian Staff who agreed on the need to reorganise and overcome the problems Simpson had noted. They agreed to raise a small ‘Corps of Electricians’ of twenty British officers and sixty other ranks, all radio specialists, who would train and develop a cadre of Russian signallers who would transform Russian military telegraphy.

Two things happened which meant that the Corps, though constituted in the UK, would never travel to Russia. First, a Major Campbell was posted to Petrograd as the representative of ‘C’ to Russian Military Intelligence and, separate from the confusion and intrigue which arose in an Embassy which already housed a Military Attaché and a General Staff liaison officer with the Russian General Staff, his presence became associated with the Electricians, and the Russians came to believe that they would be a Corps of Siginters who would likely spend their time intercepting and reading Russian traffic. The Russians told the British they didn’t need these people any more.

And, anyway, a senior Russian officer had taken Simpson’s recommendations to heart and had begun a process of creating a Russian military signal service: though it wasn’t why the decision to refuse entry to the British electricians had been taken, it was in fact true that the Russians had learned enough from Simpson and his two UK radio specialist signallers had shown the Russian Army what it needed to do, not just in terms of its own signalling, but in developing a Sigint organisation as well. The Russian Army signallers became very competent indeed, and formed a specialist unit proud of its own technical competence. When the Revolution came, and after the descent of Russia into civil war, the unit declared for the Red Army and provided a Sigint service for the Bolshevik regime.

As in the Second World War no serious intelligence relationship with the Russian ally was ever developed in spite of the efforts made. First time round, however, it isn't hard to put the blame pretty squarely in the British side.

The Prime Minister's Visit to Hut 7

The Prime Minister, Winston Churchill, visited Bletchley Park on Saturday 6 September 1941, on his way to Ditchley Park, where he would stay overnight. There are a couple of more or less plausible accounts of what happened during the visit, but his visit to Hut 7 is not one of the better known. 

Hut 7 was located north of Huts A and B, and west of Hut C, and was built early in 1940, to be occupied by the staff, led by Frederick Freeborn, who transferred there from the British Tabulating Machine Company at Letchworth and their equipment (often referred to as Hollerith machines) Hut 7 was responsible for the bulk of information processing at Bletchley Park, at its peak getting through two million punched cards each week.

I imagine that Hut 7 was chosen partly because of the number of machines it contained, partly because they could be used theatrically to impress the PM, and partly because each of the functions carried out on them could be explained to him in language he would understand, whereas, if he had been taken to see the Bombes, it would have been much harder to explain what was happening.

He would see how a message header and (say) the first ten groups of the message were punched onto cards, then see how a couple of thousand messages could be sorted: into date and time order, perhaps, or by recipient. He could see how a cipher group could be followed through several messages, and how cards could be duplicated if they were valuable as references.

All of this would be to impress upon the PM that the seemingly fantastic resources BP was requesting were not for some sort of vanity project, but rather for the machine age's version of the Room 40 he had been responsible for when it first broke into German naval codes early in November 1914.

The value of the visit came a few weeks' later when four rather naïve cryptanalysts, seeing that the holdups and shortages Bletchley Park was facing were significantly reducing the organisation's intelligence productivity, wrote to the Prime Minister asking him to unlock the delivery of resources. His answer was an instruction to his senior aides, General Ismay and Sir Edward Bridges, to 'make sure they have all they want on extreme priority and report to me that this has been done'.

Many years later Ronald Whelan MBE, one of two brothers Freeborn had brought with him to Bletchley Park in 1940 from Letchworth, remembered the visit in a memoir (TNA HW 25/22) of the work of Hut 7.

'The visit of Winston Churchill

By the time of Churchill's visit to Bletchley Park Hut 7 had become a commodious erection as compared with the modest Hut in which we had started our activities. Being a wooden structure it had been comparatively easy for workmen to tear down walls and partitions, and to tack on extensions, not once but several times, until eventually for a time we had ample accommodation for machines and operators. With such a stage to hand, Freeborn, who apart from his very high technical and administrative abilities was always a showman and an opportunist, planned a memorable demonstration of the use of Hollerith equipment in Bletchley Park on the occasion of Churchill's visit to Hut 7.

Freeborn's secretary, Miss Ellen Ford and I were waiting with Freeborn by the entrance door when Churchill strode down the path towards us, followed by three no-nonsense looking men, who were obviously his bodyguard. As Churchill entered the hut his bodyguards attempted to follow, but Churchill rounded on them and in a voice which would have done credit to that of the great huge bear, rasped "Not you", causing than to stop dead in their tracks.

On entering the Machine Room area on his exit from the Key Punching Room, the visitor was presented with a scene of intense activity. There were about 45 machine operators in action and as many or more than that number of machines. Then all the machines were halted at the same instant, and in the complete silence which followed an Introductory explanation was given to the visitor as the party stood on the threshold of the area. Then as he was conducted towards a group of twelve or more Sorters, all these machines started into action at the same moment. They were allowed to run only for a short time, and all came to rest as one, so that their function and application could be explained without distraction.

Moving from the Sorters to the Reproducers the same arrangement held; all in action on his approach, but at rest for an explanation to be given by Freeborn, the same arrangements applying for each of our various equipments.

At the conclusion of the demonstration all machines were brought into action as the visitor was conducted to the exit, but all brought to rest as he paused on the threshold as he made his farewells. But on reaching the door he turned back, first to stub out his cigar in a nearby ashtray, and then to turn to Miss Ford, to shake her hand and bid her Goodbye.

Miss Ford had a dazed look as she stared at the hand that the great man had held, then she took up the cigar butt and said it was something she would always treasure.'