A teenage boy was indecently assaulted by former TV weatherman Fred Talbot after a visit to the pub on a school camping trip left the pupil "very much the worse for wear", a court has heard.
The witness, now a man in his 50s, told of his "horror" when he awoke to find Talbot touching him in a tent when he was partially clothed.
He told jurors he used the force of his fist to knock Talbot off him and said the events left him feeling physically and mentally ill the next day.
Talbot, 67, is on trial at Lanark Sheriff Court, where he denies indecently assaulting several teenage boys on school trips to Scotland in the 1970s and 1980s.
He is further accused of lewd, indecent and libidinous practices and behaviour towards a boy aged 12 on a trip, a charge he also denies.
The witness, who cannot be named for legal reasons, told the court he was 15 when he went on a weekend excursion organised by Talbot to a place near Dumfries, in the south of Scotland, in 1979.
At that time, Talbot was a biology teacher at the school he attended in the Manchester area, the court heard.
"It was cold, dark, miserable and there was nothing to do," the witness said of the trip.
On one of the evenings, he said he was "singled out" to go to a local pub with Talbot.
The witness said he consumed eight pints and a whisky chaser over the course of the night with Talbot, recalling other boys on the trip came to the pub at some point.
Asked about his condition by fiscal depute Imran Bashir, he said: "Very much the worse for wear. I'd never had anything like that before."
The witness said his next recollection at the campsite was of his arm being pulled and the accused trying to put the pupil's hand on his (Talbot's) private parts.
The accused was also trying to perform a sex act on him, the court heard.
The witness said some of his clothing had been removed.
"My initial reaction was one of horror," he said, adding that the force from his fist hitting the teacher's chin "knocked him off me".
The witness - who also spoke of feeling "shock" and "revulsion" - said he felt ill on the trip back home because he was suffering from alcohol poisoning.
He told jurors he felt "dreadful, extremely ill, physically and mentally".
Alan Gravelle, defending, suggested to the witness the idea he was permitted to drink eight pints of lager and a whisky chaser is "a nonsense".
"No, it's not," the man replied.
Earlier, a witness on a video link from Australia told the court how he awoke in his tent to find Talbot making a sexual advance on him more than 35 years ago.
The man, 51, told the jury he found Talbot, then a teacher at his school, stroking his hand in a sexual way during a weekend field trip to the St Mary's Loch area in the south of Scotland in 1981.
"I think I had been asleep and then I was aware that my hand was being stroked in the tent," the man, who was 15 at the time, told jurors.
"The only person who could be doing that was Mr Talbot next to me."
Mr Gravelle suggested any contact may have been inadvertent and accidental.
"There's nothing in my mind that would concur with that," the man replied.
The trial, before Sheriff Nikola Stewart, continues on Thursday.