Codes and Ciphers Heritage Trust


Planning and Conservation Issues

Key Points

  • The owners of the park and the Bletchley Park trust have made available three historical buildings for sale
  • H Block is owned by TeleReal, and C and D Blocks are owned by OGC
  • Blocks C and D are unoccupied
  • Block H contains the rebuild of the Colossus Computer - the world's first programmable computer
  • English Heritage's report on the park states that D Block is the most important wartime building - a view supported by GCHQ
  • Conservation Mgmt Plan for MK states "...the rebuild of the Colossus computer should stay in H block..."
  • Blocks H and D now have Grade II listed status, and the application for Block C is being processed
  • Tony Sale's planning application for Museums in all three blocks was unanimously accepted by MK planning committee on 27th April 2005 - the permit stating that the blocks shall only be used for museums or heritage

Milton Keynes Council has from the outset taken a keen interest in developing Bletchley Park as a National and International Heritage site. A conservation area order was placed on the lower part of the Park in 1991. This was extended to cover most of the Park in 1992.

The owners of Bletchley Park and the Bletchley Park Trust, BPT, announced in September 2004 that they intended to dispose of three Historic buildings on the site namely H, D and C Blocks, and have placed them on the market through agents Atis Real Weatheralls.

Of the buildings in question, D and C Blocks are owned by the Government, Office of Government Commerce, (OGC). H Block is owned by TeleReal, the property arm of British Telecom. BPT has a 250 year lease on these buildings from OGC and TeleReal.

C and D Blocks are at present unoccupied but H Block contains the working rebuild of the Wartime Colossus Mk 2 code breaking computer which was the world's first programmable electronic computer.

English Heritage have recently released a four volume report on Wartime Bletchley Park. This identifies D Block as the most important Wartime building in the Park. This view is supported by GCHQ, the successor to the Wartime Government Code and Cipher School.

A Conservation Management Plan for Bletchley Park recently adopted by Milton Keynes Council, identifies the importance of H Block as the earliest remaining purpose built computer centre and home of the Wartime Colossus computers. It says ".. the rebuild of the Colossus computer should stay in H Block..".

The Department of Culture, Media and Sport (DCMS) have now Listed H Block and D Block Grade II and are processing an application for the Listing of C Block.

Tony Sale's Planning Application for Museums in H Block, D Block and C Block was approved by the Milton Keynes Development Planning Committee on 27th April 2005: votes, for 8 against 0. Here is the Committee paper:(.pdf 100Kb)

(Not the actual application map, but shows where the buildings are)

The Permit says that these buildings shall ONLY be used for Museum/Heritage. The Conservation Management Plan for Bletchley Park was adopted on 27th January 2005. The aim of the Conservation Management Plan is to provide further guidance (beyond what is contained in the Local Plan) for new development in Bletchley Park. The CMP provides certainty on the way in which development is intended to take place and as such is a useful tool for prospective developers, the community and planning authorities.

Here is the entry for H Block.
Date construction started May 1944
Date construction completed Sept 1944
Designed by: Ministry of Works built by MoW

Notes: the first Colossus building F Block annex, sited to the east, was demolished together with Block F. This is the second Colossus building and housed production models.


period: WWII, SIGINT Occupied as second site, but was purpose built to house Colossus

period: 1945-1992, Training suites?

period: current, Colossus reconstruction project

PPG 15 values directly associated with the building Fabric:
Architectural,low: Historical,high: Technical,low: Personal Association,low:

Sensitivity: site of Colossus, probably the worlds first production programmable electronic computer. Colossus may yet emerge as the principle reason for long term international interest in Bletchley Park, and decisions regarding this building should reflect this.

Exterior medium: Overall shape form and massing should be retained. Interior single storey low, interior remodeled as a training suites 2 storey medium, probably still WWII

Fittings high: currently houses the Colossus rebuild project, which should stay in this building if possible.

Recording: required systematic photography, measured survey.

Further investigation infrastructure, particularly Colossus power and environmental requirements

Construction type: single storey: reinforced concrete frame, brick walls, concrete floors pitched asbestos cement roof, steel windows. 2 storey steel frame, brick walls concrete floors and roof Current condition poor

Ground floor Area 1200 m 2
First floor area 135 m 2
Second floor
Total floor area 1335 m 2

Possible future uses museum, offices.

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