Codes on polymer note shine light on computer pioneer’s work
The country’s highest-value note joins the lower denominations in being printed on polymer, meaning all notes currently being printed by the bank are on plastic for the first time.
Advanced security features give the new notes an edge over the old paper notes, which will be no longer be accepted from next September, as they are harder to counterfeit.
The note is released to coincide with what would have been the birthday of the Second World War codebreaker and the bank has worked with Snapchat to create an augmented reality smartphone filter in celebration of his life and work.
The artwork on the note also pays tribute to Turing’s pioneering work with computers.
Among the new security features is a hologram on the note which change to read either “Fifty” or “Pounds” depending on which way the note is tilted.
Two hologram see-through windows are also included, which change between “50” and “£” depending on the tilt. One of the windows, which sits next to a small portrait of the Queen, features gold and green foil on one side, with silver foil on the back.
The shape of the smaller see-through window, in the bottom corner of the note, is based on architectural features at Bletchley Park, home to codebreakers in the war.
Above the hologram on one side of the note there is a 3D image of the coronation crown on a patch of silver foil. On the reverse there is a red foil patch containing the letters “AT”.
There is also a number “50” printed on the front of the note which can only be seen under ultraviolet light. This is what shopkeepers will be looking for when they check the notes behind their tills.
Turing is featured on the opposite side to the Queen’s larger portrait. His image is set against a background depicting several of his contributions to science.
There is a mathematical table and formula taken from his seminal 1936 paper On Computable Numbers, with an application to the Entscheidungsproblem, widely recognised as foundational for computer science.
The Automatic Computing Engine (ACE) Pilot Machine, one of the first electronic stored-program digital computers, which was developed as a trial model of Turing’s design.
There are also technical drawings for the British Bombe, the machine specified by Turing and one of the primary tools used to break Enigma messages in the war, along with ticker tape depicting Turing’s birth date (23 June 1912) in binary code.
It also features the following quote from Turing: “This is only a foretaste of what is to come and only the shadow of what is going to be.”