GCHQ: Why Cheltenham?

Over on Twitter, Chris Greenway asked why GCHQ came to Cheltenham, and whether anywhere else was considered. What follows is based on a booklet written by Peter Freeman, my predecessor-but-one as GCHQ Historian. That booklet is out of print, and my successor is in the process of producing a new edition. Peter covered a lot of ground about what happened in Cheltenham after the move was decided which I won't cover here.

On 1 April 1946 GCHQ began the move away from Bletchley Park. It took four days and saw a much smaller organisation than had been in existence a year earlier move to Eastcote, a former Bombe station in the London suburbs. At that time it felt logical that GCHQ should return to London: called GC&CS, it had left Broadway Buildings by St James's Park (which it shared with SIS) in August 1939. The drivers for the move were that the office space at Bletchley was too large for the much reduced (though still enormously bigger than 1939) size of the organisation, that as a national headquarters GCHQ 'should' be London-based, close to its customers, that the separation of cryptanalysis and cryptography – codebreaking and code making – had not been a success and that the pre-war staff who had patriotically endured six years in rural Buckinghamshire could reasonably expect that their posts would be returned to London.

Several problems became immediately apparent. Eastcote was scarcely St James's Park, and customers felt just as far away as they had when GCHQ was at Bletchley Park; pre-war staff who didn't have houses in West London faced conditions analogous to wartime getting to and from work. Most importantly, the world of 1946 was far from that of 1939: GCHQ wanted a headquarters – at one location and not dispersed – that could work in wartime as successfully as in peacetime. It had to have a mobilisation plan that recognised that its primary function was the production of military intelligence on the Soviet target and that would allow it to maintain the control of military Sigint it had acquired during the war and which, by 1947, the services had grudgingly accepted would be a permanent feature of UK Sigint.

All of this (it was felt) dictated a move well away from London; there was even discussion of the argument that modern communications would make distance irrelevant, and in view of the threat of nuclear warheads on long-range rockets a move right out of the UK, perhaps to Canada, should be considered. (No Canadian was consulted during consideration of this possibility, which never gained any real traction.)

The general feeling was that about a hundred miles from London was a suitable distance, and – bearing in mind the normal requirements whether in peace or war for face-to-face contacts and close liaison with central government Ministries – good rail and road connections with London would be required. The location should provide adequate numbers for local recruitment and reasonable housing and amenities for its staff; this meant GCHQ was looking for premises in or very close to a town of reasonable size.

The enormous importance of housing in the immediate post-war period was a significant part of the jigsaw: labour and materials were in short supply throughout the country, and the whole building trade was controlled by central government.

The most demanding criterion was the requirement for good telephone and teleprinter communications. The post-war GCHQ needed hundreds of circuits, which for safety should be routed via two or more paths to two or more main switching centres (GPO or military). These circuits had to be permanent and guaranteed free from requisitioning by any other department, such as the Services, in a wartime emergency.

Most importantly, GCHQ was looking for a set of vacant offices already owned by the government. There was no question of buying commercially-owned buildings, let alone of building a whole new set (though some expansion might be affordable, and the requirements of GCHQ's communications centre and specialised machinery would probably mean that modifications would have to be made).

Within these constraints the first step was to find the right part of the country on grounds of landline communications and nearby towns; the second would be to seek suitable buildings.

A number of candidate areas were considered:

a. Oxford or Cambridge were the right size, the right distance from London, and offered the possibility of recruiting staff in wartime. In particular the Cambridge area included Huntingdon, which had some advantages; Norwich was also a possibility. On the other hand there were many Service establishments, especially RAF stations, in the area and throughout East Anglia, which might pre-empt cable lines (and attract enemy attacks).

b. The Bedford-Leighton Buzzard area (which included Bletchley Park itself) had adequate communications and some amenities, but the competition from other government departments for space and communications would be severe.

c. The Liverpool-Manchester area had accommodation possibilities and the cable routes were being improved, but industrial development would absorb any capacity currently planned.

d. Shrewsbury, Exeter-Bridgwater and Taunton were also attractive (although all but Exeter were rather small towns), but communications serving the area were inadequate, a situation that was unlikely to improve.

e. The Bristol-Bath-Gloucester-Cheltenham area looked very attractive. The RAF had a major switching centre near Chippenham, the Army had one near Cheltenham, and the United States Army was said to have built up a network of cables in the area during the war. There were several large centres of population, all with good connections to London.

This last was the most promising, hut for many months all were possibilities. Then suddenly both steps in the decision were taken at once: in October 1947 a member of GCHQ on a private visit to Cheltenham heard that there was a large set of government buildings at nearby Benhall Farm (Oakley seems not to have been mentioned to him), currently occupied by the Ministry of Pensions but likely to be vacated within a year or two. He arranged to look over the buildings, representing himself as an Admiralty official interested in pensions procedures.

His report was most encouraging. There was adequate capacity for staff; a canteen, support buildings and a Ministry of Works depot adjacent. There were buses to and from Cheltenham every 10 minutes: the local corporation and people were well-disposed towards Civil Servants: and local recreational and social facilities were excellent. The other candidates remained on the list for many months, but from this moment onwards Cheltenham was the only one seriously considered by GCHQ.