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The Papers of Gordon Welchman

Reference Code: GBR/0014/WLCH

Scope and Contents

This collection contains Gordon Welchman’s personal papers, including engagement diaries, correspondence, notes, drafts, articles, and reports. Subjects include intelligence, communications, codebreaking, and computing in the twentieth century.

Much of the collection (including the correspondence with Bletchley Park alumni in WLCH 2) is book research, gathered to inform Welchman’s own writings about Second World War intelligence.


  • Creation: 1929 - 1986

Conditions Governing Access

The majority of papers are open for consultation by researchers. A small number of files are closed, which are indicated in the catalogue.

Biographical / Historical

William Gordon Welchman (known as Gordon) was born in Bristol on 15 June 1906. He held dual British and American citizenship, becoming a naturalised US citizen in 1962. In the 1920s, he studied mathematics at Trinity College, Cambridge before progressing to a research fellowship at Sidney Sussex College. He remained in Cambridge until he was recruited by the Government Code and Cypher School (GCCS, later GCHQ) at the advent of the Second World War. Welchman led Hut Six at Bletchley Park and was responsible for overseeing cryptanalysis work on German Enigma machines.

After 1945, Welchman worked briefly at John Lewis before moving to the United States and teaching the first course on computer coding at the Massachusetts Institute of Technology (MIT) (see WLCH 7). In the 1960s and 1970s, he worked and then consulted at the MITRE Corporation in Massachusetts, where he helped to develop secure communications systems such as JTIDS.

From the mid-1970s onwards, Welchman’s papers show his increasing interest in writing about wartime cryptanalysis. He believed that discussing Bletchley Park (and its equivalent institutions in other Allied nations) was crucial to improving general awareness of communications and intelligence work. Welchman’s research culminated in ‘The Hut Six Story’ (1982), a memoir describing the contribution of his codebreaking team in Hut Six. The book was controversial with both British (GCHQ) and American (NSA) intelligence services, resulting in Welchman losing his security clearances in both countries due to his descriptions of still-classified events. Nevertheless, Welchman continued writing, with two more books planned: one about “the early days of Bletchley” (which he was working on with Robin Denniston), and one about early computer development. However, he did not finish another book before his death on 8 October 1985. His article ‘From Polish Bomba to British Bombe: The Birth of ULTRA’ was published posthumously in 1986.

Welchman married three times: Katharine Hodgson (m. 1937-1959), Fannie Hillsmith (m. 1959-1970), and Elisabeth “Teeny” Huber (m. 1972). He had three children (a son and two daughters) with his first wife.


11 archive box(es)

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Other Finding Aids

A copy of this finding aid is available for consultation at Churchill Archives Centre, Cambridge.

Immediate Source of Acquisition

The papers were deposited at Churchill Archives Centre in 2022 by author Joel Greenberg at the launch for his book 'The Bletchley Park Codebreakers in their Own Words'.


This collection was catalogued by Nicole Allen in 2023, using a list of materials provided by depositor Joel Greeberg, Welchman's entry in the Oxford Dictionary of National Biography, the items themselves, and further research.


Welchman, William Gordon (1906–1985)

Language of description
Script of description

Repository Details

Part of the Churchill Archives Centre Repository

Churchill Archives Centre
Churchill College
Cambridge Cambridgeshire CB3 0DS United Kingdom
+44 (0)1223 336087