On Monday morning, the family of Alan Turing — the famed English mathematician and codebreaker whose work led to modern computer science — went to the UK prime minister’s residence at 10 Downing Street. 

They asked that the government officially pardon 49,000 men who, like Turing, were legally persecuted for having consensual sexual relationships with other men before homosexuality was decriminalized in the UK.

The family handed over a Change.org petition with more than 500,000 signatures calling for a pardon for all UK men convicted under the country’s “gross indecency” laws. Such a pardon could clear the records of some 15,000 men still alive today.