Glasgow Sheriff Court heard he also showed a third boy pornography and exposed himself in front of a fourth.

One of the victims, now aged 42, told the court he has suffered from post traumatic stress syndrome and depression since his teens because of what Bissett did to him when he was 12.

In evidence, the man, whose name was withheld for legal reasons, said: “I went to his room in the barracks, to clean his boots, but he used to tell me not to bother.

“He started giving me pornographic magazines to look at.” The man told the court that during a weekend camp at Winston Barracks, Lanark, Bissett came into the dormitory and performed a sex act on him.

He was too scared at the time to tell anyone what had happened.

Bissett was convicted after a five-day trial of sexually abusing two teenage boys and showing pornographic material to another boy and exposing himself to a fourth youngster.

The offences were committed at his then home in Ellisland Crescent, Rutherglen, Winston Barracks and at the TA cadet hut in Motherwell, between February 1971 and December 1978. Bissett denied the charges.

Sheriff Craig Henry deferred sentence until next month for background reports and a risk assessment of the danger Bissett poses to the public.