A taekwondo instructor repeatedly raped a 21-year-old woman with severe learning disabilities when he was supposed to be giving her private lessons.

Grandfather Edward Monaghan, 54, attacked the woman at his home in Helensburgh, Argyll and Bute, and at a railway station car park between October 2014 and January 2015.

The High Court in Glasgow heard that the woman had a mental capacity of a five or six-year-old child and was incapable of giving consent.

Monaghan claimed that his victim was a willing participant and admitted they had carried out some sex acts, but denied having sexual intercourse with her.

He was found guilty after a trial.

The court heard that Monaghan, a black belt, first met the woman when she was 16 and began teaching her the martial art.

He suggested to her parents, who trusted him, that she should have private lessons. He would then collect her in his car and take her either to his house or to a car park and rape her.

Prosecutor Angela Gray said: "He knew that she had attended a special school. When the woman was examined by psychologists she identified herself as a child."

Monaghan was found to have sent the woman a lewd Facebook message, to which she replied: "I don't understand."

He then messaged: "I know. You do have an innocent mind lol."

The woman's father described her as being very slow at learning, said she couldn't go out herself and needed a 24-hour care package.

Her dad said: "I trusted that man. I really trusted him."

Judge Robert Weir QC deferred sentence until next month and granted Monaghan bail with a curfew and the condition to report daily to Helensburgh police station. He was also placed on the Sex Offenders' Register.

He told Monaghan: "I will continue your bail because you are a first offender and have complied with your bail conditions. It does not reflect on any sentence that may be imposed."