Site Records

Site Name: Station Z - Air Ministry Citadel

In the grounds of In the grounds of Kodak Ltd.
Headstone Drive
Harrow
Middlesex

OS Grid Ref: TQ148898

Sub Brit site visit 3rd November 2005

No sooner had the First World War ended than the Government started to worry about what might happen if there was another war. From 1924 Britain had committees of officials examining ARP questions and this examination intensified after Hitler came to power in Germany in 1933 and as the conviction grew, based on experience of the Spanish Civil War where the view was that the bomber would 'always get through'. It was assumed, naturally enough, that the main target for enemy air raids would be central London.

It was decided early in 1936 to appoint a Minister for the Coordination of Defence and to launch an expanded five-year programme of rearmament. France ratified a bilateral pact with Soviet Russia and on 7 March Hitler sent his troops into the Rhineland in defiance of the Versailles and Locarno treaties. The Cabinet now called for contingency plans to be devised for coping with a potentially dangerous situation and among new sub-committees set up under the Committee of Imperial Defence was one on 'the location and accommodation of staffs of Government Departments on the outbreak of war'.

Chaired by Sir Warren Fisher (Head of the Civil Service), the 5-man sub-committee reported early in 1937 with a suggestion that an alternative centre of government should be planned in the London area where Ministers and possibly Parliament could be relocated if Whitehall were to become untenable. After endorsement by the Cabinet in February 1937, this work was further developed in great secrecy by a new 5-man sub-committee under Sir James Rae and resulted in two alternative schemes, one of which was for accommodating not only civil servants but also Ministers and Parliament in London's northwest suburbs; if however, this short retreat were to prove insufficient, a further withdrawal should be made to prepared accommodation in the western counties.

Photo:Station Z which consists of a 3 storey office block plus basement and sub-basement
Photo from In the grounds of Kodak Ltd.

For the 'fighting' Departments work on bombproof underground citadels was to be continued, including one for the Admiralty at Oxgate in Cricklewood and one for the Air Ministry at Harrow

When this suburban scheme was examined further in the autumn of 1938, after the Munich crisis, it was decided that the construction of four underground citadels would go ahead: one each for the three Services and a fourth which became the bombproof Emergency War Headquarters at Dollis Hill.

The Emergency War Headquarters (Paddock) and the Air Ministry and Admiralty Citadels were built as planned but that for the army at Kneller Hall in Twickenham was abandoned before work started. As with Paddock and the Admiralty Citadel at Oxgate the chosen site was within an existing government facility, HM Stationary Office where a vacant plot of land was selected.

In line with the original 1938 plan the Air Ministry citadel consisted of a three storey above ground surface block with an inner court yard. Below this was a basement roofed over by 3½ feet of reinforced concrete and below it a sub-basement protected by another 6 feet of concrete (probably in two layers); with comparable protection at the sides, the sub-basement was considered to be entirely bombproof. The building was almost identical to the Admiralty citadel in Oxgate Lane, Cricklewood.

The new Air Ministry site was ready for occupation by October 1940 as detailed in a minute sent to the Deputy Under Secretary of State for Air on 11.10.1940 (National Archive ref: Air 19/190)

"The Air Ministry Citadel is situated at the rear of HM Stationary Office premises (HMSO Printing Works) Headstone Drive, Wealdstone, Middlesex. It is known for the sake of anonymity as Z or the Stationery Office Annexe.

If a move to Z were ordered the whole of the staff of the Air Ministry Whitehall would be involved but those divisions in the (Air Ministry) Kingsway Area would not be affected.

The Whitehall Group comprises: Secretary of State (for Air), Under Secretary of State, Permanent Under Secretary and part of the departments of the Permanent Under Secretary, the Chief of the Air Staff and the department of the Chief of the Air Staff (i.e. Directorate of Signals, Directorate of Intelligence, Directorate of Operations (Home), Directorate of Operations Naval Co-operation, Directorate of Operations (Overseas), Directorate of Plans, Directorate of Public Relations, Directorate of Operations Requirements and Directorate of Ground Defence.

(They would all be relocating from the new protected Government Office in Whitehall adjacent to the cabinet war room.)

Communications: The Air ministry Citadel may be obtained on the telephone from the Cabinet Offices in Richmond Terrace or Paddock by the following means

Post war plan of the Kodak site showing Station Z

For further information and pictures of Station Z click here

Home Page