The Bank of England lists the following items that are depicted, along with a portrait of Alan Turing, on the reverse of the £50 Note that it issued in 2021:
| • | A mathematical table and formulae from Turing's seminal 1936 paper On Computable Numbers, with an application to the Entscheidungsproblem Proceedings of the London Mathematical Society. This paper is widely recognised as being foundational for computer science |
| • | The Automatic Computing Engine (ACE) Pilot Machine which was developed at the National Physical Laboratory as the trial model of Turing's pioneering ACE design. The ACE was one of the first electronic stored–program digital computers |
| • | Ticker tape depicting Alan Turing's birth date (23 June 1912) in binary code |
| • | Technical drawings for the British Bombe, the machine specified by Turing and one of the primary tools used to break Enigma–enciphered messages during WWII |
| • | A flower–shaped red foil patch, based on the image of a sunflower head, linked to Turing's morphogenetic (study of patterns in nature) work in later life |
| • | A series of background images depicting technical drawings from The ACE Progress Report |
Also shown is the following quote from an interview given by Alan Turing to The Times newspaper on 11 June 1949: "This is only a foretaste of what is to come and only the shadow of what is going to be."
© Haydn Thompson 2022