Alan Turing, the Second World War code-breaker and pioneer of computer science with a “fearless approach to daunting problems”, will appear on the Bank of England’s next £50 note.

Turing was selected from a list of nearly 1,000 eligible people who have contributed to science.

It is hoped that even more people will be inspired to learn about the groundbreaking achievements of the mathematician, whose later life was overshadowed by a conviction for which he was pardoned after death.

Bank of England governor Mark Carney made the announcement at the Science and Industry Museum in Manchester.

The new polymer £50 note is expected to enter circulation by the end of 2021.

It will feature a quote from Turing, given in an interview to the Times newspaper on June 11 1949: “This is only a foretaste of what is to come, and only the shadow of what is going to be.”

A GCHQ spokeswoman said Turing’s technical innovations “were ahead of their time and still inform and improve our work at GCHQ to help keep the UK safe”.

Turing played a pivotal role at Bletchley Park in breaking the Enigma code, an achievement which is said to have helped to shorten the length of the Second World War by years, saving millions of lives.

New £50 note
Mark Carney announces that Alan Turing has been selected to feature on the next £50 note (Peter Byrne/PA)

The Enigma enciphering machine had been used by the German armed forces to send messages securely.

He was also pivotal in the development of early computers, first at the National Physical Laboratory and later at the University of Manchester.

Turing laid the foundations for work on artificial intelligence by considering the question of whether machines could think.

Mr Carney said: “As the father of computer science and artificial intelligence, as well as war hero, Alan Turing’s contributions were far-ranging and path-breaking.

“Turing is a giant on whose shoulders so many now stand.”

Turing was homosexual and was posthumously pardoned by the Queen, having been convicted of gross indecency for his relationship with a man.

He was chemically castrated following his conviction.

Mr Carney said there had been “huge progress” in treating people fairly, irrespective of sexual orientation, since Turing’s death in 1954.

He continued: “And the Bank of England is committed to ensure our bank notes are as inclusive as possible.

“And it means featuring a range of individuals to reflect the vibrant diversity of UK society.”

Speaking about Turing, Mr Carney added: “I think it is widely recognised that his death was a tragedy, that it was deeply unfair.”

Turing’s place on the new £50 banknote means Jane Austen will continue to be the only woman, apart from the Queen, whose image will be on the Bank’s notes.

Writer Caroline Criado-Perez, who has previously campaigned to highlight the lack of women on banknotes, pointed out that three out of four of the Bank of England’s notes will continue to feature men.

She wrote on Twitter: “So that’s still 75% male & 100% white. Really disappointing, @bankofengland.”

The announcement that Turing will be celebrated on the new £50 note was welcomed.

Adrian Smith, director and chief executive of the Alan Turing  Institute, said: “Turing’s fearless approach to daunting problems and his intellectual curiosity still have a remarkable influence today across different disciplines and communities.”

Sir Dermot Turing, nephew of Alan Turing and trustee at Bletchley Park Trust, said: “Today’s announcement follows many years of work by various individuals and organisations to honour and remember the life, work and tragic death of Alan Turing.

“I am touched by all those who nominated Alan to be the face of the new £50 note, and hope today’s news will inspire more people to learn about his story and contribution to computer science.”

Iain Standen, chief executive of Bletchley Park Trust, added: “Today he is rightly considered one of the pioneers of modern computing and artificial intelligence, and his legacy continues to inspire new generations.”

Turing was chosen following the Bank’s character selection process which included advice from scientific experts.

In 2018, the Banknote Character Advisory Committee chose to celebrate the field of science on the £50 note, and the Bank received 227,299 nominations  – leading to 989 eligible figures.

A shortlist was drawn up by the committee, with the governor making the final decision.

Those also considered were Stephen Hawking, Mary Anning, Paul Dirac, Rosalind Franklin, William Herschel and Caroline Herschel, Dorothy Hodgkin, Ada Lovelace and Charles Babbage, James Clerk Maxwell, Srinivasa Ramanujan, Ernest Rutherford and Frederick Sanger.

The new banknote design features a photo of Turing from 1951, a table and mathematical formulae from a 1936 paper by Turing, and technical drawings for the British Bombe used to break Enigma-enciphered messages.

Turing’s signature from the visitors’ book at Bletchley Park in 1947 is included, alongside ticker tape depicting Turing’s birth date – June 23 1912 – in binary code.

The concept of a machine fed by binary tape featured in Turing’s 1936 paper.

The current £50 note features Industrial Revolution pioneers Matthew Boulton and James Watt.