23 June 2021
The Bank of England have issued the new polymer £50 note, featuring a portrait of pioneering mathematician Alan Turing, with the note set to become available in bank branches and at ATM’s in the coming days and weeks.
Alan Turing is perhaps best known for his codebreaking work during the Second World War.
Speaking at Bletchley Park, where Turing carried out his famous codebreaking work, Governor Andrew Bailey said:
'Our banknotes celebrate some of our country’s most important historical figures. That’s why I am delighted that Alan Turing features on the new polymer £50 note.
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'Having undertaken remarkable codebreaking work here at Bletchley Park during the Second World War, he went on to pioneer work on early computers, as well as making some ground-breaking discoveries in the field of developmental biology. He was also gay and was treated appallingly as a result.
'Placing him on this new banknote is a recognition of his contributions to our society, and a celebration of his remarkable life.'
Features on the new £50 note include:
- A photo of Turing taken in 1951 by Elliott & Fry which is part of the Photographs Collection at the National Portrait Gallery.
- A table and mathematical 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. It sought to establish whether there could be a definitive method by which any theorem could be assessed as provable or not using a universal machine. It introduced the concept of a Turing machine as a thought experiment of how computers could operate.
- 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.
- 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 quote from Alan Turing, given in an interview 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.”
- Turing’s signature from the visitor’s book at Max Newman’s House in 1947 which is on display at Bletchley Park, where he worked during WWII.
- Ticker tape depicting Alan Turing’s birth date (23 June 1912) in binary code. The concept of a machine fed by binary tape featured in the Turing’s 1936 paper.
- Two key security features can be checked to help confirm that notes are genuine:
- a metallic hologram which changes between the words ‘Fifty’ and ‘Pounds’ when the note is tilted.
- a large see-through window with a gold and green foil on the front depicting a finely detailed metallic microchip image.
- There are two green 21 spiral features based on a sunflower head (linked to Turing’s morphogenetic work in later life). The foil is silver on the back.
- A metallic hologram which changes between the words ‘Fifty’ and ‘Pounds’ when the note is tilted.
- A silver foil patch with a 3D image of the Coronation Crown.
- The Queen’s portrait in the see-through window with ‘£50 Bank of England’ printed twice around the edge. (The small clover shapes on the outside of the window are based on architectural features at Bletchley Park.)
- A smaller see-through window in the bottom corner of the note, the shape of which is based on architectural features at Bletchley Park.
- A red foil patch containing the letters ‘AT’ is based on the image of a sunflower head linked to Turing’s morphogenetic work in later life.