Hut 4 was a wartime section of the Government Code and Cypher School (GC&CS) at

Bletchley Park 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 ...

tasked with the translation, interpretation and distribution of ''

Kriegsmarine The (, ) was the navy of Germany from 1935 to 1945. It superseded the Imperial German Navy of the German Empire (1871–1918) and the inter-war (1919–1935) of the Weimar Republic. The was one of three official branches, along with the a ...

'' (German navy) messages deciphered by Hut 8. The messages were largely encrypted by Enigma machines. As the Kriegsmarine operated Enigma more securely, Hut 8 had less information for

Ultra adopted by British military intelligence in June 1941 for wartime signals intelligence obtained by breaking high-level encrypted enemy radio and teleprinter communications at the Government Code and Cypher School (GC&CS) at Bletchley Park. '' ...

than

Hut 6 Hut 6 was a wartime section of the Government Code and Cypher School (GC&CS) at Bletchley Park, Buckinghamshire, Britain, tasked with the solution of German Army and Air Force Enigma machine cyphers. Hut 8, by contrast, attacked Naval Enigma. ...

which handled Army and Air Force messages. Hut 4 also broke various hand cyphers and some Italian naval traffic.

Location

Located initially in one of the original single-story wooden huts, the name "Hut 4" was retained when the section moved to a new brick building, Block A, in 1941.

Operation

Naval Ultra was handled differently from Army and Air Force Ultra because the Admiralty was an operational HQ and could give orders during a battle; while the Imperial General Staff (Army) and Air Staff would give directives to theatre commanders general orders say to "clear the enemy out of Africa" with discretion over how to do it. Verbatim translations of naval decodes were sent to the Naval Intelligence Division (NID) of the Admiralty's Operational Intelligence Centre (OIC) in London and nowhere else (except for some naval intelligence sent directly from Bletchley to Commanders-in-Chief in the Mediterranean). Hut 4 also decoded a manual system known as the "dockyard cipher". This sometimes carried messages that were also sent on an Enigma network. Feeding these back to Hut 8 provided excellent '' cribs'' for breaking the current naval Enigma key.

People

* M. M. G. Jennings (Margaret Allan), racing driver *

J. W. B. Barns John Wintour Baldwin Barns (12 May 1912 – 23 February 1974) was a British Egyptologist, papyrologist, Anglican priest, and academic. From 1965 to 1974, he was Professor of Egyptology at the University of Oxford. Early life and education Barn ...

, later Professor of Egyptology at Oxford * Sarah Baring, later Viscountess Astor *

Osla Benning Margaret Osla Henniker-Major, Lady Henniker-Major (''née'' Benning; 23 August 1921 – 29 October 1974) was a Canadian debutante, who worked at Bletchley Park, was Prince Philip's first girlfriend, and later married John Henniker-Major (later ...

, Prince Philip's first girlfriend * Jocelyn Bostock from Lady Margaret Hall (LMH) Oxford, assistant to Hinsley *

Alec Naylor Dakin Alec Naylor Dakin (3 April 1912 – 14 June 2003) was a Fellow of Oxford College, a cryptologist at Bletchley Park, an Egyptologist and schoolmaster. Early life and family Alec Dakin was born in Mytholmroyd in the West Riding of Yorkshire in ...

Pamela Rose Pamela Rose (29 November 1917 – 17 October 2021) was an actress (as Pamela Gibson) who later worked at Bletchley Park running Naval Hut 4’s indexing section. In later life she was a trustee and chair of charities. Education and personal lif ...

* Leonard R. Palmer, later Professor of Comparative Philology at Oxford.Briggs (2011) p 148 *

Bernard Willson Harold Bernard Willson (25 February 1919–1994) was a British linguist and noted academic, who during the Second World War was the first person to decrypt the Italian Navy Hagelin C-38 code machine. He was the father of television presente ...

Note:

Frank Birch Francis Lyall "Frank" Birch, (5 December 1889 – 14 February 1956) was a British cryptographer and actor. He was educated at Eton College and King's College, Cambridge. During World War I, he served as a lieutenant commander with the R ...

and Harry Hinsley were both associated with the naval section (Huts 4 & 8).

References

Sources

Asa Briggs Asa Briggs, Baron Briggs (7 May 1921 – 15 March 2016) was an English historian. He was a leading specialist on the Victorian era, and the foremost historian of broadcasting in Britain. Briggs achieved international recognition during his lon ...

''Secret Days: Code-breaking in Bletchley Park'' (2011, Frontline Books, London) * Peter Calvocoressi ''Top Secret Ultra'' (1980, Cassell Ltd, London) {{DEFAULTSORT:Hut 04 Cryptography organizations Bletchley Park Buildings and structures in Milton Keynes