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Bletchley Park is an English country house and estate in Bletchley, Milton Keynes (Buckinghamshire), that became the principal centre of Allied code-breaking during the Second World War. The mansion was constructed during the years following 1883 for the financier and politician Herbert Leon in the Victorian Gothic, Tudor and Dutch Baroque styles, on the site of older buildings of the same name.
Government Communications Headquarters (GCHQ) is an intelligence and security organisation responsible for providing signals intelligence (SIGINT) and information assurance (IA) to the government and armed forces of the United Kingdom. Primarily based at "The Doughnut" in the suburbs of Cheltenham, GCHQ is the responsibility of the country's Secretary of State for Foreign and Commonwealth Affairs, but it is not a part of the Foreign Office and its director ranks as a Permanent Secretary.
Fish was the UK's GC&CS Bletchley Park codename for any of several German teleprinter stream ciphers used during World War II. Enciphered teleprinter traffic was used between German High Command and Army Group commanders in the field, so its intelligence value (Ultra) was of the highest strategic value to the Allies. This traffic normally passed over landlines, but as German forces extended their geographic reach beyond western Europe, they had to resort to wireless transmission.
The vulnerability of Japanese naval codes and ciphers was crucial to the conduct of World War II, and had an important influence on foreign relations between Japan and the west in the years leading up to the war as well. Every Japanese code was eventually broken, and the intelligence gathered made possible such operations as the victorious American ambush of the Japanese Navy at Midway in 1942 and the shooting down of Japanese admiral Isoroku Yamamoto a year later in Operation Vengeance.
Brigadier John Hessell Tiltman, was a British Army officer who worked in intelligence, often at or with the Government Code and Cypher School (GC&CS) starting in the 1920s. His intelligence work was largely connected with cryptography, and he showed exceptional skill at cryptanalysis. His work in association with Bill Tutte on the cryptanalysis of the Lorenz cipher, the German teleprinter cipher, called "Tunny" at Bletchley Park, led to breakthroughs in attack methods on the code, without a computer. It was to exploit those methods, at extremely high speed with great reliability, that Colossus, the first digital programmable electronic computer, was designed and built.
Room 40, also known as 40 O.B., was the cryptanalysis section of the British Admiralty during the First World War.
Alfred Dillwyn "Dilly" Knox, CMG was a British classics scholar and papyrologist at King's College, Cambridge and a codebreaker. As a member of the Room 40 codebreaking unit he helped decrypt the Zimmermann Telegram which brought the USA into the First World War. He then joined the Government Code and Cypher School (GC&CS).
Hut 8 was a section in the Government Code and Cypher School (GC&CS) at Bletchley Park tasked with solving German naval (Kriegsmarine) Enigma messages. The section was led initially by Alan Turing. He was succeeded in November 1942 by his deputy, Hugh Alexander. Patrick Mahon succeeded Alexander in September 1944.
Sir Francis Harry Hinsley, was an English intelligence officer and historian. He worked at Bletchley Park during the Second World War and wrote widely on the history of international relations and British Intelligence during the Second World War. He was known as Harry Hinsley.
Commander Alexander "Alastair" Guthrie Denniston was a Scottish codebreaker in Room 40, deputy head of the Government Code and Cypher School (GC&CS) and hockey player. Denniston was appointed operational head of GC&CS in 1919 and remained so until February 1942.
Nigel de Grey was a British codebreaker. Son of the rector of Copdock, Suffolk, and grandson of the 5th Lord Walsingham, he was educated at Eton College and became fluent in French and German. In 1907 he joined the publishing firm of William Heinemann. As he was shy and physically small, a colleague labelled him "the dormouse".
Ernst Constantin Fetterlein was a Russian cryptographer who later defected to Britain.
With the rise of easily-intercepted wireless telegraphy, codes and ciphers were used extensively in World War I. The decoding by British Naval intelligence of the Zimmermann telegram helped bring the United States into the war.
Before the development of radar and other electronics techniques, signals intelligence (SIGINT) and communications intelligence (COMINT) were essentially synonymous. Sir Francis Walsingham ran a postal interception bureau with some cryptanalytic capability during the reign of Elizabeth I, but the technology was only slightly less advanced than men with shotguns, during World War I, who jammed pigeon post communications and intercepted the messages carried.
The 1943 BRUSA Agreement was an agreement between the British and US governments to facilitate co-operation between the US War Department and the British Government Code and Cypher School (GC&CS). It followed the 1942 Holden Agreement.
Leslie Harrison Lambert, known in public as A. J. Alan, was an English magician, intelligence officer, short story writer and radio broadcaster. At the beginning of World War II he worked in naval intelligence at Bletchley Park.
The Government of the United Kingdom maintains several intelligence agencies that deal with secret intelligence. These agencies are responsible for collecting, analysing and exploiting foreign and domestic intelligence, providing military intelligence, and performing espionage and counter-espionage. Their intelligence assessments contribute to the conduct of the foreign relations of the United Kingdom, maintaining the national security of the United Kingdom, military planning, public safety, and law enforcement in the United Kingdom. The four main agencies are the Secret Intelligence Service, the Security Service (MI5), the Government Communications Headquarters (GCHQ) and Defence Intelligence (DI). The agencies are organised under three government departments, the Foreign Office, the Home Office and the Ministry of Defence.
The Hush WAACs were a group of seventeen British women who worked on the front line as codebreakers in France during World War One. After the war, two would go on to work on diplomatic codebreaking for MI1b. Although women were already working as codebreakers in Room 40 and MI1b, the Hush WAACs were the only women to serve as codebreakers at the front line during WW1.
ClaribelSpurling was an English teacher, children’s writer, and cryptanalyst who worked as a codebreaker with MI1(b) during World War I and with the Government Code and Cypher School (GC&CS). She was the only person to pass an 'impossible' test designed by the head of MI1(b) to check the quality of applicants. In civilian life, she was a schoolteacher and a warden of university halls, and she co-wrote stories and drama for children with Beatrice Clay.
MI1(b) was a department of British Military Intelligence set up during World War I for the interception and cryptanalysis of coded messages. Unlike its equivalent in the Admiralty, Room 40, where women were employed in clerical roles, MI1(b) employed women as linguists, translators, and cryptanalysts. By 1919, a third of MI1(b)’s civilian cryptanalysts and linguists were women.
References
- What happened to MI1 - MI4?
- Erskine, Ralph; Smith, Michael, eds. (2011), The Bletchley Park Codebreakers, Biteback Publishing Ltd, ISBN 978-1-84954-078-0 Updated and extended version of Action This Day: From Breaking of the Enigma Code to the Birth of the Modern Computer Bantam Press 2001
- Gannon, Paul, Inside Room 40: The Codebreakers of World War I, Ian Allan Publishing, 2011, ISBN 978-0-7110-3408-2