Bletchley Park

Bletchley Park was the headquarters of the British Military Intelligence Government Code and Cipher School during World War II. Located fifty miles north of London, on the grounds of the sprawling Victorian mansion for which it was named, Bletchley Park employed 12,000 code breakers and staff. Bletchley Park cryptologists successfully broke the major codes used by the German military and high command, creating the most advanced computing sources of the time with few resources. British cryptologists also aided United States efforts to break Japanese codes. Intelligence information gathered from Bletchley Park is credited with significantly aiding the Allied war effort and saving thousands of lives.

The beginning of Bletchley Park. Although British Military Intelligence employed code breakers during World War I, they failed to establish a permanent cryptology department in the inter-war period. In 1938, on the eve of World War II, British Military Intelligence revived the cryptology department. Drafting cryptographers from all disciplines, and heavily recruiting young men from Oxford and Cambridge, the first cryptology operations were established in London. The group's main task was to correspond with foreign code breakers in allied nations and cull information regarding their cryptology efforts against German codes.

In the summer of 1939, British Intelligence moved the cryptology department to Bletchley Park, officially dubbed Station X because it was the tenth division of the intelligence organization. A cipher school was established on the grounds to train new code breakers. As war was on the horizon, a large number of women were trained for employment at Bletchley Park. At the height of the war, three-quarters of Bletchley Park staff were women. The focus of operations at Station X shifted to active code breaking. By the outbreak of World War II in September of 1939, Bletchley Park cryptologists had already made considerable progress against some German diplomatic codes.

Early code breaking efforts. During the two years of the war, British cryptologists decoded German communications with limited success. Older codes, used for low security messages, were readily identified and broken by the Bletchley Park team. Some newer codes were broken mathematically, but decoding and translating these messages by hand proved an arduous task. By the time messages were fully understood, the information they contained was often outdated. Compounding the problem, these intercepts contained very little useful intelligence information. Since the mid-1930s, the German government had used complex cipher machines to disguise their most important communications.

The first great code breaking triumph at Bletchley Park came on August 30, 1941. A British "Y Station," one of the military listening stations that intercepted German communications, picked up a depth, a repeat transmission that used the same settings on the cipher machine. This intercept was forwarded to Bletchley Park. Cryptologists identified as "fish," the nickname for a message produced by the illusive Geheimschreiber cipher machine. Within two months, the Bletchley Park team broke the high-level German code.

To facilitate the processing of "fish" intercepts, Bletchley Park engineers borrowed an idea from plans the Polish intelligence service gave Britain before the war. They constructed a machine that aided the deciphering of intercepts, nicknamed a "bombe" because of the low, roaring noise it made while operating. The "bombe" constructed to decipher Geheimschreiber transmissions did help cryptographers to process intercepts more rapidly, but the machine required the exact synchronization of two paper tapes for printing. The tapes often broke, and the machine had to be reset. In addition, the start setting to process each intercept, the original cipher settings used by the Germans to send the message, had to be calculated by British cryptologists by hand. The process was still too complex to yield decoded intercepts ready for immediate translation to be useful to intelligence and military personnel.

Operation Ultra: breaking the German Enigma machine. Most of Germany's high-level military messages were encoded using a cipher machine called Enigma. The complex code used not only a cipher, but also an overlaying encryption to disguise the original text. The series of rotor wheels on the Enigma teleprinter gave the machine an extraordinary number of code combinations. The Germans were so confidant that the machine code was so nearly infinite in possibilities that it could never be broken. However, various intelligence services in neighboring nations had made considerable progress breaking Enigma even before the outbreak of the war. In Britain, efforts to break Enigma were known as Operation Ultra.

In the months preceding the German invasion of Poland in 1939, Polish intelligence passed on to British intelligence information on their efforts to break Enigma. Most helpful was the information Polish spies gathered on how the cipher machine operated, including sketches of the teleprinter and some of its components. With the information, Bletchley Park cryptologists found two key weak links in the Enigma code. Enigma code prohibited that any letter be encrypted as itself, and German standards of communication dictated that the same phrase begin all transmissions. Exploiting these two weaknesses, British cryptologists unraveled the Enigma code mathematically in late 1940.

Even though cryptologists could read portions of Enigma transmissions, they encountered the same delay of accessing intercepted information as they had with other codes. Another bombe was constructed that could process Enigma codes, expediting code breaking. However, cryptologists and engineers at Bletchley Park realized that another mechanical solution was needed to fully exploit German intercepts. To this end, two Bletchley Park engineers invented Colossus, the first electronic, programmable machine in 1943. Colossus not only decoded messages, but also broke through the overlaying cipher, producing a ready to translate copy of the intercept in the original German. With Colossus, Bletchley Park could decipher German communications before the intended recipients. Translated intercepts were immediately passed on to intelligence and military officials, making Bletchley Park central to the Allied war effort.

Security at Bletchley Park. Concerned that the German military and government would change encryption devises if they knew of the operation, operations at Bletchley Park were shrouded in absolute secrecy. Details of Operation Ultra and other specific code breaking missions were fully known by only four people. A special intelligence protocol was established to funnel information into and out of Bletchley Park. No one link in the chain of information knew more than two other people involved in the operation.

In order to guard Bletchley Park secrets in the event of a German invasion or bombing campaign of Britain, Bletchley Park's extensive archives of every decoded intercept and the accompanying original intercept were photographed and catalogued at the Bodleian Library at Oxford University. Code breaking equipment was supposed to be entirely disassembled, put on a nearby train to Liverpool, and then ferried to the United States if Bletchley Park were in danger of falling into enemy hands. The tight security surrounding Bletchley Park was remarkably successful. The operation was one of the few government and military outposts that was not compromised by German spies.

Legacy of Bletchley Park. The work of cryptologists and engineers at Bletchley Park is often credited with shortening the duration of the war in Europe by an estimated two to three years. Bletchley Park intelligence aided military strategy, the shipment of necessary troops and supplies, and turned the tide of the war in favor of the Allies.

German U-boats controlled the seas until Bletchley Park decoded intercepts provided military leaders and shipping interests with up-to-date fleet positions and mission reports. Ultra intelligence aided the sinking of the German destroyer, Bismarck, a great moral victor for the British Navy.

On land, Station X intelligence helped Allied forces plan their invasions of North Africa, Italy, and France. During the D-Day offensive and the subsequent Allied march across France, military field command received daily intelligence updates based on information garnered by Bletchley Park code breaking efforts.

Bletchley Park also intercepted the first dispatches relating to German prisoner of war and concentration camps. Other intercepts decoded by Bletchley Park provided Allied military leaders with the first evidence of the Holocaust.

After the war, the Bletchley Park was abandoned and the staff sworn to secrecy regarding their wartime employment. All of the deciphering equipment, including replica teleprinters, bombes, and even Colossus, were disassembled and archived or simply destroyed. By March of 1946, no trace of Station X operations remained on the grounds of Bletchley Park, with the exception of the hastily constructed outbuildings, known as huts, which housed offices and staff. British Military Intelligence, known after the war as MI-6, did not dissolve the Government Cipher School or cryptology department. The department was moved to MI-6 headquarters in London, and then to Cheltenham in 1952 where its main mission was the decoding of Soviet Cold War-era communications.

Although its contribution to the war effort was highly significant, the exploits of Bletchley Park were not fully known until details regarding Operation Ultra and Station X were finally declassified in 1989. The continued secrecy of Bletchley Park allowed American engineers in 1945 to take credit for the invention of the world's first computer, ENIAC, built two years after Colossus. No member of the Bletchley Park staff betrayed the secrets of Station X until the government opened its files to the public.

Further Reading

Books

Hinsley, F. H. British Intelligence in the Second World War. Cambridge: Cambridge University Press, 1988.

Hinsley, F. H. and Alan Stripp, eds. Codebreakers: The Inside Story of Bletchley Park. Oxford: Oxford University Press, 2001.

Smith, Michael. Station X: Decoding Nazi Secrets. London: TV Books, 2000.

During World War II, codebreakers at Bletchley Park decrypted and interpreted messages from a large number of Axis code and cipher systems, including the German Enigma machine. For this purpose, the Bletchley Park mansion, pictured here, was soon joined by a host of other buildings. The mansion's façade is an idiosyncratic mix of architectural styles.

Bletchley Park, also known as Station X, is an estate located in the town of Bletchley, in Buckinghamshire now part of Milton Keynes, England. During World War II, Bletchley Park was the location of the United Kingdom's main codebreaking establishment. Codes and ciphers of several Axis countries were deciphered there, most famously the German Enigma. The high-level intelligence produced by Bletchley Park, codenamed Ultra, is frequently credited with aiding the Allied war effort and shortening the war, although Ultra's effect on the actual outcome of WWII is debated.

Bletchley Park is now a museum and is open to the public.

Early history

The lands of the Bletchley Park estate were formerly part of the Manor of Eaton, included in the Domesday Book in 1086. Browne Willis built a mansion in 1711, but this was pulled down by Thomas Harrison, who had acquired the property in 1793. The estate was first known as Bletchley Park during the ownership of Samuel Lipscombe Seckham, who purchased it in 1877. The estate was sold on 4 June 1883 to Sir Herbert Samuel Leon (1850–1926), a financier and Liberal MP. Leon expanded the existing farmhouse into the present mansion.^{[1] [2]}

The architectural style is a mixture of Victorian Gothic, Tudor and Dutch Baroque and was the subject of much bemused comment from those who worked there, or visited, during World War II. Leon's estate covered 581 acres (235 hectares), of which Bletchley Park occupied about 55 acres (22 ha). Leon's wife, Fanny, died in 1937,^[3] and in 1938 the site was sold to a builder, who was about to demolish the mansion and build a housing estate. Just in time, Admiral Sir Hugh Sinclair, (Director of Naval Intelligence, head of MI6 and founder of the Government Code and Cypher School) bought the site with his own money (£7,500), having failed to persuade any government department to pay for it.^[4] The fact that Sinclair, and not the Government, owned the site was not widely known until 1991 when the site was nearly sold for redevelopment. The first government visitors to Bletchley Park described themselves as Captain Ridley's shooting party.

The estate was conveniently located on the "Varsity Line" (now largely closed) between the Universities of Oxford and Cambridge, which supplied many of the codebreakers, at its junction with the main West Coast railway line from London. It was also chosen for its proximity to a major road (the A5) to London and to a route for telephone trunk lines.

Wartime history

The cottages in the stableyard were converted from a tack and feed house. Early work on Enigma was performed here by Dilly Knox, John Jeffreys and Alan Turing. The windows at the top of the tower open into a room used by Turing.

Just before war broke out Biuro Szyfrów revealed Poland's achievements on decrypting German Enigma codes to British intelligence. The British used the information given to them by Poland as a basis for their own attempts to decrypt German Enigma signals. The "first wave" of the Government Code and Cypher School (GC&CS) moved to Bletchley Park on 15 August 1939. The main body of GC&CS, including its Naval, Military and Air Sections was on the ground floor of the house, together with a telephone exchange, a teleprinter room, a kitchen and a dining room for all the staff. The top floor was allocated to MI6. The prefabricated wooden huts were still being erected, and initially the entire "shooting party" was crowded into the existing house, its stables and cottages. These were too small, so Elmers School, a neighbouring boys' boarding school was acquired for the Commercial and Diplomatic Sections (Smith, 1998 page 2-3).

A wireless room was set up in the mansion's water tower and given the code name "Station X",^[5] a term now sometimes applied to the codebreaking efforts at Bletchley as a whole. The 'X' simply denotes the number '10' in Roman numerals, as the this was the tenth such station to be opened. Due to the long radio aerials stretching from the wireless room, the radio station was moved from Bletchley Park to nearby Whaddon to avoid drawing attention to the site.^[6][7]

Listening stations - the Y-stations (such as the ones at Chicksands in Bedfordshire and Beaumanor Hall in Leicestershire, the War Office "Y" Group HQ) - gathered raw signals for processing at Bletchley. Coded messages were taken down by hand and sent to Bletchley on paper by motorcycle couriers or, later, by teleprinter. Bletchley Park is mainly remembered for breaking messages enciphered on the German Enigma cypher machine, but its greatest cryptographic achievement may have been the breaking of the German "Fish" High Command teleprinter cyphers.

The intelligence produced from decrypts at Bletchley was code-named "Ultra". It contributed greatly to the Allied success in defeating the U-boats in the Battle of the Atlantic, and to the British naval victories of Battle of Cape Matapan and the Battle of North Cape.

When the United States joined the war Churchill agreed with Roosevelt to pool resources and a number of American cryptographers were posted to Bletchley Park. Whilst the British continued to work on German cyphers, the Americans concentrated on the Japanese ones.

The only direct action that the site experienced was when three bombs, thought to have been intended for Bletchley railway station, were dropped on 20-21 Nov 1940. One bomb exploded next to the dispatch riders' entrance, shifting the whole of Hut 4 (the Naval Intelligence hut) two feet on its base. As the huts stood on brick pillars, engineers just winched it back into position whilst work continued inside.

An outpost of Bletchley Park was set up at Kilindini, Kenya to break and decipher Japanese codes.^[1] With a mixture of skill and good fortune, this was successfully done: the Japanese merchant marine suffered 90 per cent losses by August 1945, a result of decrypts.

Cryptanalysis

Among the famous mathematicians and cryptanalysts working there, perhaps the most influential and certainly the best-known in later years was Alan Turing.

From 1943, Colossus, one of the earliest digital electronic computers, was constructed in order to break a German teleprinter cipher known as TUNNY. Colossus was designed by Tommy Flowers and built by the British Post Office's Dollis Hill facility. The Colossus series machines were operated at Bletchley Park.

Some 9,000 people were working at Bletchley Park at the height of the codebreaking efforts in January 1945,^[8] and over 10,000 worked there at some point during the war.^[9] A number were recruited for various intellectual achievements, whether they were chess champions, crossword experts, polyglots or great mathematicians. In one, now well known instance, the ability to solve The Daily Telegraph crossword in under 12 minutes was used as a recruitment test. The newspaper was asked to organise a crossword competition, after which each of the successful participants was contacted and asked if they would be prepared to undertake "a particular type of work as a contribution to the war effort". The competition itself was won by F H W Hawes of Dagenham who finished the crossword in less than eight minutes.^[10]

After the war

At the end of the war, much of the equipment used and its blueprints were destroyed. Although thousands of people were involved in the decoding efforts, the participants remained silent for decades about what they had done during the war, and it was only in the 1970s that the work at Bletchley Park was revealed to the general public. After the war, the site belonged to several owners, including British Telecom, the Civil Aviation Authority^[11] and PACE (Property Advisors to the Civil Estate). GCHQ (Government Communications Headquarters), the post-war successor organisation to GC&CS, ended training courses at Bletchley Park in 1987.

The local headquarters for the GPO was based here and housed all the engineers for the local area together with all the support they needed. The Eastern Region training school was also based in the park and later part of the national BT management college which was relocated here from Horwood House. There was also a teacher training college.

By 1991, the site was nearly empty and the buildings were at risk of demolition for redevelopment. On 10 February 1992, Milton Keynes Borough Council declared most of the Park a conservation area. Three days later, on 13 February 1992, the Bletchley Park Trust was formed to maintain the site as a museum devoted to the codebreakers. The site opened to visitors in 1993, with the museum officially inaugurated by HRH the Duke of Kent, as Chief Patron, in July 1994. On 10 June 1999 the Trust concluded an agreement with the landowner, giving control over much of the site to the Trust.^[12]

The Trust is volunteer-based and relies on public support to continue its efforts. Christine Large was appointed Director of the Trust in March 1998. On 1 March 2006, the Park Trust announced that Simon Greenish had been appointed Director Designate, and would work alongside Large in 2006,^[13] taking over on 1 May 2006.

In October 2005, American billionaire Sidney Frank donated £500,000 to Bletchley Park Trust to fund a new Science Centre dedicated to Alan Turing.^[14]

A team headed by Tony Sale has undertaken a reconstruction of a Colossus computer in H block.^[15] Another team has undertaken a rebuild of the bombe, led by John Harper.^[16] On 6 September 2006, the Trust demonstrated^[17] that the Bombe was back in action.

A 1:40 scale model of a German World War II U-boat, used in the film Enigma and later donated to the Bletchley Park museum.

In 1994, a team led by Tony Sale began a reconstruction of a Colossus Mk II computer at Bletchley Park. Here, in 2006, Tony supervises the breaking of an enciphered message with the completed machine.

A project to construct a working replica of a bombe is nearing completion.

Buildings

Hut 1 was the first hut to be constructed.

Hut 4, sited adjacent to the mansion, was used during wartime for naval intelligence. Today, it has been refurbished as a bar and restaurant for the museum.

Hut 6 in 2004.

The huts were designated by numbers; in some cases, the hut numbers became associated as much with the work which went on inside the buildings as with the buildings themselves. Because of this, when a section moved from a hut into a larger building, they were still referred to by their "Hut" code name.

Some of the hut numbers, and the associated work, are:

• Hut 1 — the first hut, built in 1939^[18]
• Hut 3 — intelligence: translation and analysis of Army and Air Force Enigma decrypts
• Hut 4 — Naval intelligence: analysis of Naval Enigma decrypts
• Hut 6 — Cryptanalysis of Army and Air Force Enigma
• Hut 8 — Cryptanalysis Naval Enigma
• Hut 10 — Meteorological section^[19]
• Hut 11 — The first Bombe building^[20]
• Hut 14 — main teleprinter building^[21]

In popular culture

• Bletchley came to wider public attention from the 1999 documentary series "Station X".[2]
• Bletchley featured heavily in Enigma and its 2001 film adaptation
• The BBC Radio 4 sitcom Hut 33 is also set at Bletchley.[3]
• The ITV television miniseries "Danger UXB" featured the character Steven Mount who was a codebreaker at Bletchley, and was driven to a nervous breakdown (and eventual suicide) by the stressful and repetitive nature of the work.
• A fictionalized version of Bletchley Park is featured in the novel Cryptonomicon by Neal Stephenson.

See also

• List of people associated with Bletchley Park
• Newmanry
• Testery
• Y-stations
• Arlington Hall
• National Cryptologic Museum
• Danesfield House

External links

• Maps and aerial photos for 51°′″N 0°′″W / 51.997, -0.742Coordinates: 51°′″N 0°′″W / 51.997, -0.742
  • Satellite image from WikiMapia or Google Maps
  • Street map from Multimap or GlobalGuide
  • Aerial image from TerraServer

Wikimedia Commons has media related to:

Bletchley Park

• Bletchley Park Trust
• Bletchley Park — Virtual Tour — by Tony Sale
• Telecoms at Bletchley Park
• Photographs, history, maps and other information about Bletchley Park
• Codes and Ciphers Heritage Trust
• "New hope of saving Bletchley Park for nation" (Daily Telegraph 3 March 1997)
• 2366 (Bletchley Park)ATC Squadron
• BBC Radio 4 programme "Hut 33" - June 2007 Sitcom by James Cary, set in Bletchley Park in 1941.
• A photographic tour of the disused Enigma buildings at Bletchley Park
• Bletchley Park - Where the World as we know begun

References

1. ^ Edward Legg, Early History of Bletchley Park 1235– 1937, Bletchley Park Trust Historic Guides series, No. 1, 1999
2. ^ Keith A. F. Woodward, Welcome to West Bletchley — The Birthplace of the Information Age, site retrieved 23 January 2006.
3. ^ Valentin Foss "Bletchley Park"
4. ^ Smith, Micheal [1998]. Station X: The Codebreakers of Bletchley Park. Channel 4 Books, page 20. ISBN 978-0752221892. 
5. ^ Bob Watson, "How the Bletchley Park Buildings Took Shape", Appendix in F. H. Hinsley & A. Stripp, Codebreakers: The Inside Story of Bletchley Park, 1993
6. ^ The Secrets of Bletchley Park - Souvenir Guide, Bletchley Park Trust, 2nd edition, 2003
7. ^ Pidgeon, Geoffrey [2003]. Station X - The Secret Wireless War. Universal Publishing Solutions Online Ltd. ISBN 978-1843752523. 
8. ^ Smith, 1998, pp. 175-176
9. ^ Smith, 1998, pp. 175-176
10. ^ The Daily Telegraph, "25000 tomorrow" 23 May 2006
11. ^ BellaOnline "Britain's Best Ket Secret"
12. ^ Bletchley Park Trust "Bletchley Park History"
13. ^ Bletchley Park® Trust Appoints Director Designate, Bletchley Park News, 1 March 2006
14. ^ Action This Day, Bletchley Park News, 28 February 2006
15. ^ Tony Sale "The Colossus Rebuild Project"
16. ^ John Harper "The British Bombe"
17. ^ The Guardian "Back in action at Bletchley Park, the black box that broke the Enigma code."
18. ^ Tony Sale "Bletchley Park Tour", Tour 3
19. ^ David Kahn, 1991, Seizing the Enigma, pp. 189-190
20. ^ Tony Sale "Bletchley Park Tour", Tour 4
21. ^ Beaumanor & Garats Hay Amateur Radio Society "The operational huts"

Further reading

• Ted Enever, Britain's Best Kept Secret: Ultra's Base at Bletchley Park, 3rd edition, 1999, ISBN 0750923555.
• F. H. Hinsley and Alan Stripp, eds. Codebreakers: The Inside Story of Bletchley Park, Oxford University Press, 1993.
• Christine Large, Hijacking Enigma: The Insider's Tale, 2003, ISBN 0470863463.
• Hugh Sebag-Montefiore, Enigma: the Battle for the Code, London, Weidenfeld & Nicolson, 2000.
• Michael Smith, Station X, Channel 4 Books, 1998. ISBN 0330419293 or ISBN 0752221892
• Doreen Luke's - My Road to Bletchley Park
• Peter Hilton, "Reminiscences of Bletchley Park, 1942-1945", AMS History of Mathematics, Volume 1: A Century of Mathematics in America, AMS, Providence, RI, 1988,

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