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BofE unveils new £50 note

Source: Bank of England

Today, Governor Andrew Bailey unveils the design of the new £50 banknote featuring the scientist Alan Turing.

He will be joined by Stephen Fry and Dr Simon Singh, who will reflect on the note, and the choice to feature Alan Turing on it. Following its public unveil today, the polymer £50 will be issued for the first time on 23 June 2021, which coincides with Alan Turing’s birthday.

The polymer £50 note contains advanced security features, completing our most secure set of Bank of England polymer banknotes yet. The note, like the £20, incorporates two windows and a two-colour foil, making it very difficult to counterfeit. There is also a hologram image which changes between the words ‘Fifty’ and ‘Pounds’ when tilting the note from side to side.

One of the benefits shared by all our polymer banknotes is that they last longer than paper notes and they stay in better condition during their use. This note, like the polymer £10 and £20 will contain a tactile feature to help vision impaired people identify the denomination.

The polymer £50 note will join the Churchill £5, the Austen £10 and the Turner £20, meaning all Bank of England banknotes are now available in polymer. The public will begin to see the new £50 from 23 June 2021 as the notes enter general circulation. The public can continue to use paper £50 notes as usual. Notice will be given at least six months ahead of the date when the old paper £50 is withdrawn.

Commenting on the new note, Governor Andrew Bailey said: “There's something of the character of a nation in its money, and we are right to consider and celebrate the people on our banknotes. So I’m delighted that our new £50 features one of Britain’s most important scientists, Alan Turing. Turing is best known for his codebreaking work at Bletchley Park, which helped end the Second World War. However in addition 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”.

The new £50 note will feature the signature of Sarah John, the Bank’s Chief Cashier. She said: “This new £50 note completes our set of polymer banknotes. These are much harder to counterfeit, and with its security features the new £50 is part of our most secure series of banknotes yet. These security features are common across all our banknotes, so if you can check one, you can check them all.”

Director of GCHQ Jeremy Fleming said: “Alan Turing’s appearance on the £50 note is a landmark moment in our history. Not only is it a celebration of his scientific genius which helped to shorten the war and influence the technology we still use today, it also confirms his status as one of the most iconic LGBT+ figures in the world. Turing was embraced for his brilliance and persecuted for being gay. His legacy is a reminder of the value of embracing all aspects of diversity, but also the work we still need to do to become truly inclusive.”


Alan Turing is perhaps best known for his codebreaking work during the Second World War. In recognition of this, the Bank of England have collaborated with GCHQ on the intelligence and cyber agency’s toughest puzzle ever - based on the Turing £50 bank note design. GCHQ’s Turing Challenge, a set of 12 puzzlesOpens in a new window, has been put together by intelligence staff at GCHQ, where problem solving and a diverse mix of minds are at the heart of its work to help protect the UK from increasingly complex threats. The puzzle will launch on the morning of 25th March. Could you be the next Alan Turing?
Primary schools project

Although famous for his work on codebreaking and computing, Alan Turing is less well known for his discoveries in the field of biology. Turing was a pioneer of morphogenesis, where he used mathematics to understand how natural patterns like the spiral formation of the seeds in a sunflower head, and the arrangement of spots on a leopard can form.

We want to get children excited about maths and science, and show them how these subjects relate to the natural world. So we have teamed up with the School of Mathematics and Statistics at the University of Sheffield, who have designed a project for primary schools nationwideOpens in a new window. Alan Turing’s biological mathematics can be broken down into an algorithm that requires only addition, subtraction, multiplication and division. He discovered that by repeating the algorithm over and over again, beautiful patterns would emerge. Using a series of template lesson plans, primary schools can perform these calculations collectively, acting as computers to discover if Turing’s mathematics can recreate the pattern of a giant puffer fish.

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 note 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.

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