The Square Peg - Location Enquiry (part 2)
In answer to your question, a 'militia camp' was a hutted camp built during the the run-up to or during WW2. The buildings within were generally of the wooden "spider" variety as well as 'wriggly tin' Nissen huts. Some buildings such as gymnasia, camp cinemas etc were of a more substantial brick or block structure. They were built as a temporary measure intended only for the duration of the war. However, due to the additional accommodation requirements of post-war National Service as well as the utilisation of several as Displaced Persons (very often Polish) camps, many survived for some considerable period after the war.
Some militia-type camps were sited within or near to existing permanent camps, others were sited remotely.
For your information, the Carry On Sergeant location work was filmed at Stoughton Barracks, Guildford, Surrey.
This was a permanent barracks site and was the regimental depot of the the Queens Royal Surrey Regiment. It was vacated by the MoD some years ago. The fort-like structure you allude to is a "Cardwell Keep". It is typical of the type incorporated in most of the county regimental barracks built in 1870s as a result of the Cardwell reforms.
Although most of Stoughton Barracks has been entirely redeveloped for housing, Stoughton Barracks' Cardwell Keep exists yet, having been converted into residential flats. Other examples of the type exist at York, Hounslow, Lincoln, Kingston, Taunton and elsewhere.
I'm not sure about Private's Progress. I don't know if I've ever seen it.
However, "Tunes of Glory" starring Alec Guinness, John Mills and Dennis Price was filmed at Stirling Castle, which until about 1968 served as the regimental depot of the Argyll & Sutherland Highlanders. Evocative stuff!
Jan A Flaszynski