A man who says he was sexually assaulted by a Manchester United caretaker when he was 14 has broken his silence for the first time, revealing the lifelong trauma of an encounter at the club's former training ground that he says has haunted him for nearly four decades.

The alleged victim — granted anonymity by the UK's High Court after bringing a claim against the club — says Billy Watts assaulted him at The Cliff in Salford in November 1986, during the first week of Alex Ferguson's reign as United manager. Watts, who died in 2009, served as caretaker, kitman and groundsman at the training ground for years.

The man, now in his fifties, says he was drawn to The Cliff out of love for United, hoping to see Ferguson and collect autographs. After tipping off goalkeeper Gary Bailey about two boys who had stolen a pair of football boots, he says Watts lured him into the building, fed him a roast chicken dinner next to his boyhood hero Bryan Robson, and then launched a sexual attack.

"He sexually assaulted me. He grabbed at my crotch and started pulling at the top of my trousers, trying to undo them. I broke free. I ran, I scattered. I was absolutely petrified," he told The Athletic.

The man says the abuse has scarred his entire adult life — leading to depression, failed relationships, a gambling disorder, homelessness and an intense aversion to being touched. He says that aged 19 he went to the top of a multi-storey car park in Manchester and contemplated suicide. "I've had him in my head all my life," he said. "I didn't tell anyone. As a kid, nobody knew."

He launched his claim — XYZ v Manchester United Football Club Limited — in November. United reached an out-of-court settlement in March without admitting liability. It is believed to be the first time the club has been sued over an incident of this nature since football's child sex-abuse scandal broke a decade ago, with other clubs typically paying out low five-figure sums.

United was made aware in 2016 of multiple allegations against Watts, which it reported to the independent Sheldon inquiry commissioned by the Football Association. The inquiry's findings detailed claims that Watts made inappropriate sexual comments, pulled an individual into an office, followed someone into a sauna and wrestled with him, and tried to touch another boy in the showers. Youth-team players reportedly referred to him as a "pervert".

Watts was disciplined by the club in 1989 and "redeployed" to Old Trafford, away from The Cliff and youth-team players. United have previously said they believe he left the club within months and took a job as a cleaner at a police station.

Despite the settlement, the man says United has never apologised — a contrast he draws with Manchester City, which invited more than 100 victims of serial abuser Barry Bennell in for emotional meetings with senior executives. "It's about getting closure," he said. "Instead, it feels to me like United have taken the attitude of, 'This has happened, we've paid you off, we've swept you under the carpet and we don't have to deal with you any more.'"

United said in a statement: "As we said at the time, we cooperated fully with the Sheldon review... While it would not be appropriate to comment on individuals, we take any allegations of this nature extremely seriously and have met and listened to anyone who has come forward with dignity and respect."

For the alleged victim, the pain remains raw. He undergoes psychotherapy and says some days he simply cannot get out of bed. He still wonders whether there were other victims: "I've often thought to myself, 'Who else has he done this to?' Or was I a test person? He had a lot of access to young people."