Alan Turing's 'Delilah' papers: Rare Book of the Week

An important archive of Alan Turing's unpublished Second World War papers has been saved from leaving the UK following a collaboration between various institutions.

After his vital war work on the Enigma machines at Bletchley Park, in 1943 Turing began building a portable voice encoder for short-distance military transmissions code-named 'Delilah'. With electrical engineer Donald Bayley he built a prototype at Hanslope Park, now the home of HMGCC (His Majesty’s Government Communications Centre), and the couple kept a logbook of their results. Bayley also kept handwritten notes of lectures Turing gave to Hanslope Park engineers about the project, including loose pages of diagrams, calculations, and explanations.

Very little of Turing's unpublished work has survived, and the papers were liable to leave the country but were saved for the public thanks to a major donation from trading firm XTX Markets, Friends of the Nations' Libraries,  and support from the National Heritage Memorial Fund and King's College. They will now be held permanently by King's College Cambridge where Turing studied as an undergraduate and was made a Fellow. The Turing Archive was founded in 1960 following a donation of his papers by his mother, Sara.

"It’s brilliant news that the Friends of the Nations’ Libraries charity has successfully campaigned to save Alan Turing’s vital notebooks," said Secretary of State for Culture Media and Sport Lisa Nandy. "Turing was not only a pioneering figure in science and mathematics, but also a national hero. This is a powerful example of what can be achieved when private and charitable sectors come together. After a government export ban was placed on the notebooks, this collaboration has ensured that these treasures will be preserved for years to come.”

The archive consists of more than 40 pages of unpublished ‘Delilah’ project notes written by Turing and Bayley. After digitization they will become part of the Turing Papers online archive, freely available to scholars and students around the world. 

Alex Gerko, founder and co-CEO, XTX Markets, said: “The 'Delilah’ papers are a unique collection of notes from one of the nation’s greatest mathematicians. It’s important that this archive remains in the UK and is made publicly accessible, so we are thrilled to be part of that effort."