## Ahead of His Time — Mathematician and computer science pioneer Alan Turing will appear on UK currency

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### Announcement and rationale
- Bank of England Governor Mark Carney revealed the next face of the United Kingdom’s £50 note as Alan Turing (1912–54) at the Science and Industry Museum in Manchester.
- The bank earmarked the note “for science,” describing Turing as “a visionary as well as a revolutionary” and “an outstanding mathematician whose work has had a considerable impact on how we live today.”
- The new £50 celebrates Turing’s influence as “a profound and inventive thinker of the modern digital age,” particularly the legacy of his 1936 paper “On Computable Numbers,” which proposed a computing machine and is credited with laying foundations for computer science.

### Technical contributions and historical impact
- Turing’s seminal 1936 paper “On Computable Numbers” imagined the very concept of modern computing.
- At Bletchley Park, Turing developed the code-breaking Bombe machine (adapted from a Polish design) and made advances in decryption that, building on work from Polish mathematicians, led to cracking the German Enigma code.
- His team’s work is widely credited with expediting the war’s end and saving millions of lives.
- Postwar work helped create the world’s first commercial computers and articulated philosophical and logical foundations for artificial intelligence.

### Selection process and public reception
- The Bank of England ran a months-long “Think Science” campaign that elicited nearly a quarter-million nominations from the public.
- A committee of scientists and central bank officials produced a short list that included Rosalind Franklin, Stephen Hawking, and Srinivasa Ramanujan.
- Public response to Turing’s selection has been positive; Sarah John, the Bank of England’s chief cashier, noted that “Turing’s work has resonated with people” and that his life story “helped demonstrate that some of the prejudices of the past were really quite unjust and that we’ve come a very long way, but also highlighted how far we still have to go in society.”

### Personal persecution, apology, and legal redress
- Turing, a gay man, was arrested and convicted of “gross indecency” for a private relationship; his government security clearance was revoked, effectively ending his career.
- To avoid prison, he submitted to chemical castration.
- Turing’s death at the age of 41 was ruled a suicide.
- The British government issued a posthumous apology in 2009; he later received a formal royal pardon.
- In 2017 legislation known as the “Alan Turing law” was passed, pardoning those convicted under the long-rescinded antigay laws of the time.

### Banknote design, materials, and timeline
- The back of the new £50 note will feature photos of Turing and an early computer developed using his designs, along with technical drawings and mathematical formulas from his 1936 paper.
- A photo of Turing and a composite image representing his ideas and inventions will appear on the reverse side of the new £50 notes, scheduled to be issued in late 2021.
- The £50 will be printed on polymer for the first time: described as much harder to counterfeit, more resilient, and having a lower carbon footprint than paper.
- The £5 and £10 notes have already come out on polymer, with the polymer £20 set to be issued in 2020.
- The £50 was last redesigned in 2011.

### Cash usage context and cultural notes
- Cash use in the United Kingdom is falling: “Just 28 percent of UK transactions were in cash in 2018, down from 40 percent in 2016,” according to Sarah John.
- Despite declining cash use, the Bank of England emphasizes that physical currency serves everyday practical purposes for many and has cultural significance: “People really do care about these banknotes and see them as a symbol of our country.”
- Turing will join three other famous British figures on current banknotes: Sir Winston Churchill (on the £5), Jane Austen (on the £10), and J. M. W. Turner, who replaces Adam Smith on the £20 note next year.

*Source: Finance & Development, December 2019 — “Ahead of His Time” by Melinda Weir*

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_Source: https://www.imf.org/-/media/files/publications/fandd/article/2019/december/alan-turing-on-uk-currency-weir.pdf_