David Bonney realised his employer, the Royal Air Force, was investigating his sexuality within minutes of entering the guard room at RAF Mount Batten, a military base near Plymouth. It was 1991 and Bonney, then a 21-year-old medical assistant, had just been escorted from his post at the medical centre by military police. He sat down in the guard room, opposite the duty staff, and the interrogation began.

“Questions about my sex life,” says Bonney, now 55. “Questions about witnessing me with other gay people. Questions about things I said on the phone to my mother.” He says there was shouting, swearing, banging on the desk. “Threats to me, threats to my career, threats to my family.” Bonney hadn’t told anyone in the military that he was gay. Before 2000, it was illegal for gay people to serve in the British armed forces and he knew a confession would cost him his career. “They wanted to get rid of me,” he says. “Anything they could to just manipulate me into confessing, to frighten the hell out of me.”

The initial interrogation took two hours. The RAF’s investigation into Bonney’s sexuality lasted two years. He says he was questioned more than a dozen times, spied on, threatened and intimidated.

When Bonney did confess, in October 1993, he was court martialled. He received a dishonourable discharge, a criminal record, multiple fines and was sentenced to six months in detention – one month of which was in solitary confinement. They would have taken his medals, too, had he not hidden them. The solitary confinement was, he says, a vindictive decision, he says, because “I made them work for two years to try to get rid of me” before he confessed.

Bonney served four months in prison, before being let out early for good behaviour. He is believed to be the last person in the UK to be imprisoned for being gay. Three decades later, he is still dealing with the fallout.