Alan Turing was granted a posthumous royal pardon in 2013. Queen Elizabeth II signed the pardon on 24 December 2013 for his 1952 conviction for gross indecency.
Turing had been prosecuted after acknowledging a relationship with another man, at a time when male homosexual activity was criminalised in Britain. He accepted chemical castration through hormone treatment instead of imprisonment, and the conviction damaged his life and career.
The pardon followed a public campaign led by Liberal Democrat MP John Leech, with support from scientists including Stephen Hawking. The government ultimately used the royal prerogative of mercy rather than waiting for a statutory pardon bill to complete its parliamentary passage.
The pardon was announced in December 2013, although Queen Elizabeth II was reported as formally pronouncing it in August 2014. That later date can cause confusion, but the standard answer to the year of Turing’s posthumous royal pardon is 2013. A broader legal amnesty, commonly called the Alan Turing law, followed in 2017.