THE family of codebreaker Alan Turing handed in a petition seeking pardons for other gay men persecuted for their sexuality just hours after his story won an Oscar.

Turing’s relatives were visiting Downing Street to hand in the petition – signed by more than 523,000 people – to demand the government pardons thousands of other British men convicted under historic homophobic laws.

It came just hours after screenwriter Graham Moore won the Oscar for best adapted screenplay for The Imitation Game, which stars Benedict Cumberbatch as Turing.

Rachel Barnes, Turing’s great-niece, 52, from Taunton, said that although her great uncle received a royal pardon in 2013, the family wanted everyone convicted under the Gross Indecency Law to be pardoned.

She said the campaign's success, with people signing the petition across 74 countries, had been "absolutely phenomenal" and was largely down to the popularity of the film.

"The publicity of the film has obviously helped significantly with this petition," she said.

"It is really, really exiting that we received an Oscar last night for the screenplay. It's an incredible day for the whole of the Turing family.

"Benedict Cumberbatch's portrayal was nothing short of incredible.

"I never met Alan Turing myself but according to my aunt, when she first saw the film, (she said) Benedict was Alan.

"Nobody could have done the performance better, so we are so glad and so grateful to Benedict Cumberbatch that he chose to play the role of Alan Turing in this film."

Turing's work cracking German military code Enigma was vital to the British war effort against Nazi Germany.

But in 1952 he was convicted for gross indecency with a 19-year-old man, was chemically castrated, and two years later died from cyanide poisoning in an apparent suicide.

Cumberbatch's Oscar-nominated portrayal of Turing has brought the pioneering scientist's story to a wider audience.

The film follows him from his days working as a Second World War code breaker at Bletchley Park to his work at Manchester University, which saw him hailed as the father of modern computing, and his tragic death.

The editor of Attitude Magazine, Matthew Todd, who was also at Downing Street, said: "I think Alan Turing is a massively iconic figure in the fight against homophobia.

"The Imitation Game really showed the public what happened to him – a lot of people didn't even know who he was five or ten years ago.

"I think it was Winston Churchill who said that no one made more of a contribution to winning the war for the Allied Forces than he did.

"He did so much - we'd probably all be speaking German now – and yet he was persecuted.

"It just seems so incredibly unfair and outrageous and he is a symbol people can relate to and understand how horrifically unfair those times were to gay and bisexual men."

Gay rights campaigner Peter Tatchell was involved in drafting an open letter, with Cumberbatch, Stephen Fry and Ms Barnes, asking for pardons to be extended to other gay men.

He said that every man convicted under Britain's homophobic laws – estimated at 50,000-100,000 – should be pardoned, not just the 49,000 found guilty of gross indecency.

Tatchell said: "All these men deserve a pardon, like the one that was granted to Alan Turing.

"His pardon is much deserved but he should not be singled out for special treatment.

"Unfairly, no such pardon has been extended to the tens of thousands of other gay victims – not even to other high-profile victims such as Lord Montague and Sir John Gielgud."