Second World War codebreaker Alan Turing’s ‘Delilah’ project papers at risk of leaving the UK

• The wartime documents are valued at £397,680 
• Export bar is to allow time for a UK institution to acquire the papers

An export bar has been placed on Alan Turing’s unpublished Second World War papers relating to the ‘Delilah’ project, which developed a portable encryption system for use in military operations.  

The papers are valued at £397,680 (inclusive of VAT of £16,280 which can be reclaimed by an eligible institution), and are at risk of leaving the UK unless a domestic buyer can be found to acquire them. 

Following Turing’s groundbreaking work on the Enigma machines at Bletchley Park, he began work on the ‘Delilah’ project at Hanslope Park to develop a portable encryption system or voice scrambler to protect military secrets in the field.

The papers consist of two bound notebooks and six separate gatherings of loose sheets. It comprises the notes of Alan Turing (1912-54) and Donald Bayley (1921-2020) relating to the World War Two project ‘Delilah’. 

Unpublished evidence of Alan Turing’s work has rarely survived. Turing himself did not usually keep research notes, working drafts, or correspondence. This collection of papers dating from 1943 to 1945 sheds light on some of Turing’s most inventive, secret, and overlooked work.

Shortly after the Second World War ended in 1945, the Delilah machine was complete and Turing was able to demonstrate the working machine successfully, which showed a recording of one of Winston Churchill’s speeches, using a system which encrypted and decrypted communications from telephone and radio devices.

Alan Turing’s work prefigured our modern digital world and his work at Bletchley Park is seen as being crucial to ending the Second World War early and saving many lives.  His post-war work formed the foundations of computer science as we know it today.  Alan Turing was later awarded an OBE for his work during the Second World War.

Arts Minister Sir Chris Bryant said:

The Delilah project papers offer unique insights into the extraordinary mind of Alan Turing, who is famed for decoding the Enigma machines, being instrumental in ending the Second World War and saving many lives. 

The British mathematician was central to the development of our modern digital world. It is right that a UK buyer has the opportunity to purchase these papers to give people the opportunity to continue to study and appreciate his work as an important part of our national story.

The Minister’s decision follows the advice of the Reviewing Committee on the Export of Works of Art and Objects of Cultural Interest. The Committee found that the papers met the first and third Waverley criteria for their outstanding connection with our history and national life and their outstanding significance for the study of the history of computing, as well as Alan Turing’s mathematical knowledge of electrical engineering.

RCEWA Chair Andrew Hochhauser KC said:

The United Kingdom owes a debt of gratitude to Alan Turing. His extraordinary work on the Enigma project at Bletchley Park played a major part in winning World War Two and saved so many lives. Turing is closely connected to our modern digital world. He is generally accepted to be the founder of computer science and is also widely considered to be the father of Artificial Intelligence.

The regard in which he is held is illustrated by the fact that in 2019 he was voted by a BBC audience the most iconic person of the twentieth century. He appears on the current £50 note. Explaining the Bank of England’s choice, the then Governor of the Bank of England, Mark Carney, observed, ‘All around us, his legacy continues to hold. Turing is a giant on whose shoulders so many now stand.’

The decision on the export licence application for the papers will be deferred for a period ending on 15 November 2024 (inclusive). At the end of the first deferral period owners will have a consideration period of 15 Business Days to consider any offer(s) to purchase the papers at the recommended price of £397,680 (inclusive of VAT of £16,280 which can be reclaimed by an eligible institution). The second deferral period will commence following the signing of an Option Agreement and will last for four months.

Notes to editors

1. Organisations or individuals interested in purchasing the papers should contact the RCEWA on 02072680534 or rcewa@artscouncil.org.uk .

2. Details of the object are as follows: two bound notebooks and six separate gatherings of loose paper sheets. It comprises the papers of Alan Turing (1912-54) and Donald Bayley (1921-2020) relating to the World War Two project ‘Delilah’. The papers date principally from 1943 to 1945, with some later additions. The material is divided as follows: Laboratory notebook (Turing and Bayley) (70 folios; 4to; 258 x 204mm). Papers on the Bandwidth theorem (Turing) (2 folios; 4to; 289 x 220mm). ‘Red form’ notes: mathematical diagrams, calculations and explanations written on the reverse of wireless-telegraphy intercept forms (Turing and Bayley) (20 folios; frayed; 4to; 250 x 189mm). ‘Determination of cut-off volts’: mathematical calculations, written on reverse of a wireless-operator log sheet (Turing) (1 folio; frayed; 4to; 249 x 197mm). ‘Faltung’: notes on the mathematics of convolutions, with diagram of mushroom, on reverse of radio log sheet (Turing) (1 folio; frayed and creased; 4to; 262 x 195mm). Notebook of notes taken by Bayley at Turing’s lectures delivered at Hanslope Park (90 folios), followed by notes taken by Bayley at university (140 folios) (Bayley) (230 folios; 4to; 278 x 235mm). Notes on different electrical problems (Turing) (2 folios) and summary notes on topics covered in Turing’s lectures (Turing, Bayley, and unidentified) (11 folios) (13 folios; 4to; 288 x 215 mm), two foolscap folios (325 x 200mm) one folio (227 x 288mm). Notes on a mathematical problem (Turing) (2 folios; 288 x 215mm)
3. Provenance: Donald Bayley, thence by descent; sold at Bonham’s 14 November 2023
4. The Reviewing Committee on the Export of Works of Art and Objects of Cultural Interest is an independent body, serviced by Arts Council England (ACE), which advises the Secretary of State for Culture, Media and Sport on whether a cultural object, intended for export, is of national importance under specified criteria.