For more than half a century John Crawford's crime has cast a shadow over his life; a permanent stigma etched into the files of the national police database. His conviction in 1959 was for consensual sex with another man – which is no longer a crime – and based on a confession extracted only after weeks of beatings in a police cell.

But 51 years later, Crawford has been told he is legally bound to disclose his criminal record for "buggery", received when he was just 19, when applying to work with vulnerable people. The retired butler, now 70, is seeking to clear his name in what he hopes will be a landmark legal campaign against the residual consequences of laws which, although expired, continue to persecute homosexuals.

Crawford, from London, discovered his conviction for a sexual offence was still registered on the police national computer (PNC) eight years ago, after seeing the results of a routine criminal records check conducted when he applied to work as a volunteer at Wormwood Scrubs prison.

"I saw John Crawford. 1959. Charged on two counts of buggery," he said. "Since then, I've analysed my life and found out the amount of my jobs that I've lost because I've got a criminal record." Now a volunteer who feeds patients at hospitals, Crawford is currently looking for work, and is compelled to disclose his conviction each time he gives his time to charity.

Under the current rules, he could be prosecuted if he fails to mention his buggery conviction under the Sexual Offences Act 1956. "What I want to do is apply for voluntary work and, when it comes to the box on the application form that says 'do you have a criminal record', I want to be able to say no," he said.

Yesterday, Crawford's lawyers informed the justice secretary, Jack Straw, that unless the rules are changed they will initiate judicial review proceedings at the high court to challenge Rehabilitation of Offenders Exceptions Order 1975, which compels those working with vulnerable people to disclose their conviction history, even if the record is spent or deleted. They argue the existing system "criminalises" Crawford's sexuality and "condones" his original conviction.

Crawford initially contacted the gay rights group Galop, which is regularly contacted by gay men seeking to delete their convictions.

Crawford has never told friends about his conviction, a secret he even kept from his ex-partner of 25 years. His ordeal began after being posted to Aldershot barracks in Hampshire for military service.

When a gay friend at the barracks went absent without leave, military police turned their attention to Crawford. "They obviously knew he was gay, but they hadn't got anything on him – other than being camp. But they had got me. And if I knew him, then I must be one as well."

Crawford was held in a cell for three weeks, during which he was deprived of sleep by being forced to sit on a chair at night. "They badgered me and badgered me to admit I was a 'fucking queer', and I wouldn't." Then they decided to call in the civilian police.

These officers, he said, started a daily beating that involved wrapping him in blankets while was kicked and punched on the floor. He said he was then placed in a yard each day. Overlooking the yard, he recalled, there was a grassy embankment where hundreds of cadets would sit twice a day to drink tea.

"Can you imagine in the 50s? Oh look there's the 'fucking queer'. I had this from hundreds of people twice a day. I had to sit in this yard. I couldn't go anywhere."

Finally he relented to the pressure and confessed to being gay. Under duress, he told them about Derek, his 22-year-old partner who, months later, found himself with Crawford in the dock at Winchester crown court where both were convicted.

Laws prohibiting gay sex began to be watered down from 1967. It was not until 2004 that offences of consensual buggery between men were completely repealed.

Some forces proactively "weeded out" convictions for repealed crimes from the PNC, but others did not.

Crawford was told by police that his conviction would remain on the database until his 100th birthday, after all 43 police forces in England and Wales had been instructed to freeze the process of deleting or "stepping down" criminal records.

The new guidance was issued by the Association of Chief Police Officers (Acpo) after a Court of Appeal ruling in October. Hampshire police agreed to treat Crawford as an "exceptional" case and delete his record from the PNC last month, after being threatened with judicial review by Crawford's lawyer, Anna Mazzola of Hickman and Rose. Despite the deletion, however, Crawford is still compelled to disclose the conviction if he wishes to work with vulnerable people.

"According to the current state of the law, it is irrelevant that the conviction was for an offence which has since been decriminalised on the basis that it was discriminatory," Mazzola said.

Hounded for homosexuality



Last year Gordon Brown issued an official public apology for the British government's treatment of Alan Turing, the pioneering mathematician who helped develop the modern computer. In 1952, Turing was found guilty of gross indecency after starting a sexual relationship with a 19-year-old man. Instead of going to prison, Turing accepted treatment with female hormones, and was disqualified from continuing secret cryptological work for the state. He died in 1954, apparently killing himself by eating an apple laced with cyanide.

In 1953, Sir John Gielgud, right, was arrested after trying to pick up a man in a public toilet who turned out to be an undercover policeman. He was found guilty of "persistently importuning for immoral purposes", his conviction was leaked to the papers and he was told by the British embassy in Washington to abandon a planned US production of The Tempest as he might prove "an embarrassment".

In 1954, Lord Montagu of Beaulieu, then a 28-year-old socialite and the youngest peer in the House of Lords, was jailed for a year after being arrested as part of a crackdown on homosexuals following the defection of gay spies Guy Burgess and Donald Maclean to the Soviet Union. He was convicted along with the Daily Mail journalist Peter Wildeblood and the Dorset landowner Michael Pitt-Rivers in a sensational case that made headlines around the world. The trial is nowadays viewed as a catalyst for the ­government's repeal of laws which made homosexuality illegal.

Helen Pidd