The new polymer £50 note is coming on 23 June 2021 and features the mathematician Alan Turing.
It will be the last of the Bank’s collection to switch from paper to polymer and in keeping with Alan Turing’s work, the note is said to be its most secure yet.
Alan Turing’s portrait is based on a photo taken in 1951 by Elliott & Fry which is part of the Photographs Collection at the National Portrait Gallery.
Alan Turing provided the theoretical underpinnings for the modern computer. While best known for his work devising code-breaking machines during WWII, Turing played a pivotal role in the development of early computers first at the National Physical Laboratory and later at the University of Manchester. He set the foundations for work on artificial intelligence by considering the question of whether machines could think. Turing was homosexual and was posthumously pardoned by the Queen having been convicted of gross indecency for his relationship with a man. His legacy continues to have an impact on both science and society today.
The design on the reverse of the note celebrates Alan Turing and his pioneering work with computers. It features:
- 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.
- The flower-shaped red foil patch on the back of the note is 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.
“This is only a foretaste of what is to come and only the shadow of what is going to be” is a quote from Alan Turing, given in an interview to The Times newspaper on 11 June 1949 and also features on the new note. So does Turing’s signature which was taken from the visitor’s signature book on display at Bletchley Park Trust in 1947, where he worked during WWII.
The work of Alan Turing, who was educated in Sherborne, Dorset, helped accelerate Allied efforts to read German Naval messages enciphered with the Enigma machine. His work is said to have been key to shortening World War Two and saving lives.
Less celebrated is the pivotal role he played in the development of early computers, first at the National Physical Laboratory and later at the University of Manchester.
In 2013, he was given a posthumous royal pardon for his 1952 conviction for gross indecency. He had been arrested after having an affair with a 19-year-old Manchester man, and was forced to take female hormones as an alternative to prison. He died at the age of 41. An inquest recorded his death as suicide.
Andrew Bailey, the governor of the Bank of England, said: “He was a leading mathematician, developmental biologist, and a pioneer in the field of computer science.
“He was also gay, and was treated appallingly as a result. By placing him on our new polymer £50 banknote, we are celebrating his achievements, and the values he symbolises.”
Key security features on the new note:
Tilt the note from side to side. Check the words change between ‘Fifty’ and ‘Pounds’.
See through windows
Look at the metallic image over the main window. Check the foil is gold and green on the front of the note and silver on the back. Within the two gold foil squares on the front of the note, the image changes between ’50’ and a ‘£’ symbol when the note is tilted.
Look for a second, smaller window in the bottom corner of the note.
The Queen’s portrait in the see-through window
A portrait of the Queen is printed on the window with ‘£50 Bank of England’ printed twice around the edge.
Silver foil patch
A silver foil patch contains a 3D image of the coronation crown. You will find this above the main see-through window on the front of the note.
Red foil patch
A metallic, red foil patch contains the letters ‘AT’. You will find this on the back of the note, directly behind the silver crown on the front of the note.
Feel of polymer and raised print
The note is printed on polymer, which is a thin and flexible plastic material. On the front of the note, you can feel raised print. For example, on the words ‘Bank of England’ and in the bottom right corner, over the smaller window.
The printed lines and colours on the note are sharp, clear and free from smudges or blurred edges. If you use a magnifying glass, you will see the value of the note written in small letters and numbers below the Queen’s portrait.
Under a good quality ultraviolet light, the number ’50’ appears in bright red and green on the front of the note, against a duller background.
On the front of the note (the side with raised print), there are four clusters of raised dots in the top left hand corner. This tactile feature helps blind and partially sighted people identify the value of the note.
The higher the value of a note, the larger it is. This note is approximately 146mm x 77mm.
A unique serial number is printed horizontally and vertically on the back of the note. The horizontal number is in the bottom right corner. It is made up of multi-coloured letters and numbers, which increase in height from left to right. The vertical number runs down the left-hand side and the numbers and letters are the same height and colour.
The international copyright symbol is included on the front and back of the note, below the ‘Fifty Pounds’ text.