Former chancellor of the exchequer Ken Clarke today denied molesting a young actor, saying the allegation was "like Martians landing".
Ben Fellows, 40, from Birmingham, alleged that the heavyweight politician had plied him with alcohol and carried out the sexual assault in the office of political lobbyist Ian Greer during a cash-for-questions sting operation by ITV's The Cook Report in 1994.
In the autumn of 2012, he told national news reporters about the alleged assault, and stories were published in print and online, jurors at the Old Bailey were told.
He went on to make a statement to police after being interviewed by officers as part of Operation Fairbank - the high profile investigation into Westminster historic child sex abuse.
In it he claimed he had been assaulted while working as an undercover actor for ITV's Cook Report and there were a number of people who had also worked on the show at the time and were aware of the alleged assault.
Fellows is on trial at the Old Bailey accused of perverting the course of justice by making up a false claim against Mr Clarke.
Giving evidence, Mr Clarke was asked if there was any truth in Fellows' allegation.
He replied: "It was quite a detailed allegation about place, incident - nothing to do with me.
"Apparently while chancellor of the Exchequer I was hanging around the office of Ian Greer and groped a man.
"My recollection was it was like Martians landing."
Mr Clarke, who has been an MP for 45 years, said he was visited by police in June 2013 who informed him of Fellows' claim - something he was already aware of.
He said: "I was already aware of it before then. I was first alerted by my son who uses the internet and he spotted somebody called Ben Fellows was making rather nasty allegations against me on the internet which upset my son and upset me as well.
"My staff made attempts to get it taken down but it was hopeless.
"By the time the police arrived I was aware what there was on the internet and newspapers. This guy for some reason was making this allegation against me over and over again trying to publicise it."
Mr Clarke went on to deny knowing Mr Greer or going to his Westminster office.
He became emotional as he described Fellows as a "stalker".
He told jurors that he "never had the compulsion" to grope a man. He added: "It's preposterous. It's off the Richter scale. It was a remarkable series of events."