An exhibition of items from the life of gay computer genius and Second World War code-breaker Alan Turing was opened at Bletchley Park, Buckinghamshire yesterday by Top Gear presenter James May.

“The Life and Works of Alan Turing” exhibition includes a rebuilt Delilah, the secret speech system that Turing had begun work on during the Second World War, an official letter which was written to his mother twenty years after his death telling her for the very first time about her son’s “vital importance to the outcome of World War II” and a teddy bear called Porgy on whom he would practise lectures.

The exhibition follows a campaign to save rare collection of Alan Turing’s work last year with private donations.

James May told ITV news at the launch: “He almost certainly shortened the war and quite possibly saved the country. Remember in the U-boat war we were within two or three weeks of being starved out of existence and if it hadn’t been for the code-breaking activities here led essentially by Turing, who was the pioneer, then we’d have lost and the world would be a different place. So Alan Turing is a hero of the nation, he must be.”

Iain Standen, CEO of the Bletchley Park Trust, describing the exhibition, said: ”The Life and Works of Alan Turing depicts a man who was not only a brilliant and visionary mathematician and codebreaker but also a beloved son, an accomplished sportsman and a man of humour and sensitivity.

“The exhibition makes a complex subject accessible to all, inspiring mathematicians of the future and giving long-awaited recognition to the short but brilliant life and legacy of Alan Turing, the father of computing. I am also delighted that this exhibition has been long-listed for the Art Fund Prize 2012, very fittingly, in this, the Turing Centenary Year.”

Bletchley Park will host November’s pre-launch of LGBT History Month 2013.

Tony Fenwick, co-chair of LGBT History Month said: “This is the early stages of what promises to be a fantastic year. Bletchley Park is a unique museum and a fantastic resource. I am holding the next LGBT History Month Pre-launch here because I want to ensure that everyone leaves school knowing who Alan Turing was, what he did and how he was destroyed by the state’s homophobia.”

Turing died in 1954, ingesting cyanide two years after being prosecuted and chemically castrated for homosexuality.

In 2009, after a campaign led by Richard Dawkins, Stephen Fry, Peter Tatchell and supported by PinkNews.co.uk, 30,805 people demanded that the then prime minister Gordon Brown issue an apology for Turing’s treatment on behalf of the British government. Mr Brown agreed to do so.

A recent campaign to grant Turing a pardon was rejected by the government as Turing was “properly convicted of what at the time was a criminal offence”, Justice Minister Lord McNally said, though it “now seems both cruel and absurd”.

He added that the “law at the time required a prosecution and, as such, long-standing policy has been to accept that such convictions took place and, rather than trying to alter the historical context and to put right what cannot be put right, ensure instead that we never again return to those times.”