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Bletchley Park
World War II codebreaking centre

Bletchley Park is an estate in the town of Bletchley, Milton Keynes (UK). During WWII, Bletchley Park, or BP for short, was the UK's main codebreaking centre. The codes and ciphers of many countries were broken there, such as messages from the German Enigma, the Geheimschreiber and the Lorenz SZ-40/42 machines. It's the place where brilliant people like Alan Turing, Gordon Welchman, Dylwyn Knox and about 12,000 others helped shortening the war by several years [1].

BP is now a museum that is open to the public every day. If you are interested in the history of code and ciphers, BP is well worth a real-life visit. Many war-time buildings, such as the mansion, the cottage, the stableyard, H-Block, B-Block and some huts are still in existence.

The image on the right shows the Mansion, which is one of the most prominent buildings on the site. But there is much more to see. BP has an interesting collection of cipher machines, such as Enigma, Lorenz SZ40/42, Siemens T-52 Geheimschreiber and much, much more.
  
The Mansion at Bletchley Park

Furthermore, the on-site National Museum of Computing 1 (TNMOC), is home to Colossus, Heath Robinson and the Bombe — the machines that were used during the war to break the Enigma and Lorenz cipher machines of Nazi-Germany. They are operational and are demonstrated regularly.

  1. TNMOC is an independent trust with its own admission fee and a separate entrance.

The Mansion at Bletchley Park
The Mansion at Bletchley Park
The Cottage at Bletchley Park where Alan Turing worked in isolation on solving the Naval Enigma
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The Mansion at Bletchley Park
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The Mansion at Bletchley Park
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The Cottage at Bletchley Park where Alan Turing worked in isolation on solving the Naval Enigma

Exhibitions
In the past, BP hosted a variety of other museums and collections, including the Churchill Collection, the Diplomatic Wireless Service (DWS), the Milton Keynes Model Railway Society, the Toys and Memorabilia Collection and the re-enactment group 65th Nachrichten Abteilung.

Following a series of reorganisations at the museum, and refurbishment of several wartime huts, these collections have been discontinued, whilst the huts have become part of the Bletchley Park Museum. Visit the Bletchley Park website for the latest information.

Other exhibitions
  • The National Museum of Computing (TNMOC)
    Probably one of the largest collections of computers is on display in H-Block, one of the former war-time buildings. The museum shows the full history of computing and many of the machines can actually be operated. You will certainly recognise some old friends here. TNMOC is a separate entity that is not linked to the Bletchley Park Trust. It is also the home to the Colossus Rebuild (see below) and the Heath Robinson Rebuild.

  • The Colossus Rebuild Project (H-Block)
    Colossus was the first programmable electronic digital computer, developed at BP during WWII to break the German Lorenz cipher. After the war, Colossus was kept secret for many years and all machines were destroyed. In 1994, a team led by Tony Sale started the reconstruction of a Colossus. An ambitious task that was completed in 2006. The machine is now fully operational [2] and is part of TNMOC.  More

  • Bombe rebuild project
    Another ambitious task carried out at BP is the rebuild of a Bombe; the machine that was used to break the German Enigma messages during WWII. Started around 1995 by a team of volunteers led by John Harper, this task was completed in 2007. The machine is now operational and is regularly demonstrated to the public at TNMOC [3].  More
Discontinued exhibitions
  • Diplomatic Wireless Service (Hut 1)
  • Bletchley Park Post Office
  • Bletchley Park Garage
  • The Churchill Collection
  • Home Front Display (part of B-Block exhibition)
  • Maritime Display
  • Light Infantry at Pegasus Bridge
  • Pigeons at War
  • The Projected Picture Trust
  • The Toys and Memorabilia Collection
  • 65th Nachrichten Abteilung
  • Milton Keynes Amateur Radio Society
  • Milton Keynes Model Railway Society
Map of Bletchley Park
Click to see more

In the years following WWII, the layout of the Bletchley Park site has changed somewhat. Furthermore, part of the grounds of been sold for housing development, and the location of the main entrance was moved from Wilton Avenue to Sherwood Drive, accross the street from the Bletchley railway station. The map above shows the layout of the Bletchley Park site in 2012. Click the map for a closer look, or download it as a PDF here.
Enigma Display
Block B at Bletchley Park houses one of the most impressive collections of Enigma machines in the world. The image on the right shows the gallery that was opened in 2009. It allows the public to view a variety of Enigma models from all sides.

There is a standard 3-wheel Enigma I, a Naval M4, the famous G-312 Abwehr Enigma, the commercial Enigma K, the rare Enigma T (that was built for the Japanese) and some special machines that were modified at BP during WWII.

 More about Enigma

  
The Enigma gallery at Bletchley Park. Click for a larger view.

Bombe rebuild project
During WWII, British codebreakers Alan Turing and Gordon Welchman developed a mechanical machine, called the Bombe, that was used for breaking German messages created on the famous Enigma cipher machine.

As none of the original Bombe machines has survived, a team led by John Harper has built a fully operational replica which was completed in 2007. The machine is now being demonstrated.

 More about the Bombe

  
Working Bombe replica at Bletchley Park Museum

TUNNY Gallery
During WWII, the Germans used the high-end Lorenz SZ-40/42 cipher machine for messages at the highest level of OKW, the German High Command. It was known as TUNNY by the codebreakers. Heath Robinson was the first machine that was built to help breaking the Lorenz cipher. It was developed by GPO Engineers Tommy Flowers and Frank Morell.

In 2001, Tony Sale built a working replica of this machine, which is now on display at the computer museum (TNMOC) in Block H.

 About Heath Robinson

  
The Heath Robinson rebuild at TNMOC

Colossus rebuild project
As the Heath Robonson machine had a few problems and limitations, GPO engineer Tommy Flowers developed and built Colossus, the first programmable electronic computer.

After the war, all Colossi were destroyed or dismantled. In 1991, a team led by Tony Sale started rebuilding Colossus, using more than 1750 valves. It is now fully operational and on permanent display at the Computer Museum.

 More about Colossus

  
The Colossus Rebuild at TNMOC


TNMOC
The National Museum of Computing

Probably one of the largest collections of computers in the world, is on display in H-Block — one of the former war-time buildings. The museum shows the full history of computing and many of the machines can actually be operated. You will certainly recognise some old friends here. Note that TNMOC is a separate entity that is not linked to the Bletchley Park Trust in any way. It is also the home to the Colossus Rebuild, the Bombe Rebuild and the Heath Robinson Rebuild.

 More about TNMOC

The Enigma gallery at Bletchley Park. Click for a larger view.
Working Bombe replica at Bletchley Park Museum
The Heath Robinson rebuild at TNMOC
The Colossus Rebuild at TNMOC
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The Enigma gallery at Bletchley Park. Click for a larger view.
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Working Bombe replica at Bletchley Park Museum
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The Heath Robinson rebuild at TNMOC
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The Colossus Rebuild at TNMOC

History
The name Bletchley Park dates back to 1877, when Samuel Lipscomb Seckham purchased the estate and built a farm house. Six years later, on 4 June 1883, it was bought by Sir Herbert Samuel Leon (1850-1926) who was a financier and Liberal MP. He expanded Seckham's farm house with a mixture of architectural styles into what is now known as The Mansion [1].

The image on the right shows the mansion around 1908. It was taken from a Kingsway Real Photo postcard that was date-stamped 8 DEC 1908, which means that the photograph must be older than that. At that time, the estate was still owned by Sir Herbert Leon and his wife Fanny.

After Fanny died in 1937, the site was sold to a builder in 1938 and plans were made for the demolition of the mansion. However, before the site with its typical mansion was destroyed, it was bought by Admiral Sir Hugh Sinclair, then Director of Naval Intelligence and head of MI6.
  
Image of Bletchley Park taken from a Kingsway real-photo postcard of 1908.

Bletchley Park was considered a convenient location, as it was within walking distance from the Bletchley railway station, right at the junction of the railway lines between Oxford and Cambridge (the Varsity Line) and the line from London to the north. As we now know, the universities of Oxford and Cambridge would supply a significant number of code-breakers during the war.

In order to disguise the true identity of the park, the first government visitors were announced as Captain Ridley's shooting party. The Government Code and Cypher School (GC&CS) officially moved to Bletchley Park (BP) on 15 August 1939, when the first wave of code-breakers arrived. The rest is history. During the war, some 12,000 people worked at BP, 80% of whom were women. They were sworn to secrecy and it wasn't until Admiral Frederick Wintherbotham's book The Ultra Secret came out in 1974, that some of them started talking about their war-time work at BP.

GCHQ logo. Click here for more information about GCHQ.

After the war, the park had various owners and remained in use for several purposes. It was used, for example, by the General Post Office (GPO), later British Telecom (BT), Property Advisors to the Civil Estate (PACE) and the Government Communications Headquarters (GCHQ, the post-war successor to GC&CS). The latter closed its training facilities at Bletchley Park in 1987.


By 1991 the estate was largely abandonned and plans were afoot for demolition of all buildings. On 10 February 1992 however, most of the park was declared a conservation area by the the Milton Keynes Borough Council. Three days later the Bletchley Park Trust was established, with the intention to turn the estate into a museum. This was largely the result of an active campaign by Tony Sale and a group of interested people. Finally, in 1993, the museum opened to visitors.

Initially the museum was open to the public every other weekend and the facilities at the park were limited. There was virtually no carpet and the roofs of some of the huts were leaking. But it told the fascinating story of the codebreakers so well. Today, Bletchley Park is turned into a modern attactive museum with all facilities that you can think of. And it is open every day.


Past events
Documentation
  1. Detailed map of Bletchley Park
References
  1. Wikipedia, Bletchley Park
    Retrieved March 2008.

  2. Tony Sale, Code and Ciphers
    Website by the first curator of Bletchley Park.

  3. John Harper, The Bombe Rebuild Project
    Website, showing the progress and the various stages of the project.
Further information
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© Crypto Museum. Created: Tuesday 14 July 2009. Last changed: Saturday, 24 September 2022 - 06:38 CET.
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