A school tutor, who does not wish to be named for fear of damaging his professional reputation, told The Mirror he was groped by the late TV star after meeting him on a family outin
The teacher, now aged in his 40s, said: "I've lived with this memory for years, but have always feared that saying something in public could damage my career.
"We met Jimmy on a day out. I was with my family and he came over and sat with us. I could feel him rubbing my leg under the table - and then moving up to my crotch.
"When I told my family later, they didn't take it seriously. They said I was imagining it or exaggerating and that Jimmy Savile was a good man.
"But I've always known he was a paedophile and I'm glad that all of this has finally surfaced. It's only a shame he isn't around to face charges. I'd like to see him stripped of his knighthood and acknowledged as the child abuser that he was."
Audio recording from the programme Savile's Travels has emerged appearing to reveal him behaving inappropriately with a young girl.
The girl, who is clearly distressed, is heard being made to promise the presenter that he is "the only one in my life", but also telling him "get off me" and "get off my backside".
It is not clear whether the excerpt, revealed by Channel 4 News, was ever broadcast.
A detective will lead a team from the Met's child abuse investigation command, who will contact all the alleged victims and work with the BBC.
Other potential victims are being encouraged to contact their local police forces or the children's charity NSPCC for support, in the wake of an ITV exposé of Savile that was watched by 1.9 million people.
However Scotland Yard insisted it had not opened an official investigation into the Radio 1 DJ and Top of the Pops star, who died last year aged 84.
The Met said in a statement: "The Metropolitan Police Service has today, Thursday 4 October, agreed to take the national lead in assessing the recent information regarding allegations made against the late Jimmy Savile.
"The assessment will be undertaken by the Serious Case Team of the Met's Child Abuse Investigation Command under the leadership of Detective Superintendent David Gray.
"Our priority will be to ensure a proportionate and consistent policing response putting the victims at the heart of our enquiries. It is too early to say how many individual allegations there are, and we will be making contact with all those concerned in due course. It is not an investigation at this stage.
"We will be working closely with the BBC investigations unit.
"Anyone else with information is urged to make contact with their local police so that any further information can then be passed to us."
It came as the BBC pulled two archive editions of its chart show from television schedules, because they had been presented by Savile.
A spokesman for the corporation said it was appropriate to "postpone" the broadcasts while allegations against the former star remained a "live issue".
So far more than a dozen women have claimed that Savile forced himself on them when they were teenagers, sometimes on BBC premises. The singer Coleen Nolan has also said that he asked her to join him at a hotel when she was just 14.
Police forces in Surrey, Sussex, Northampton and Jersey, as well as the Met itself, have confirmed that they have received recent allegations.
In the ITV documentary broadcast on Wednesday night, a woman told how she and two other girls from a children's home in Surrey were invited to London before being abused in a dressing room at Television Centre by Savile, Gary Glitter and a third household name.
Karin Ward told Exposure: The Other Side Of Jimmy Savile: "I saw Gary Glitter have sex with a girl in Jimmy Savile's dressing room. I didn't see it completely but that's what was going on and nobody batted an eyelid.
"Jimmy Savile had a [14-year-old girl] on his lap and he had his hand up her skirt. The girl Gary Glitter was having sex with also came from Duncroft [school]. I think she might have been not quite 14."
She said she was "freaked out" after the other TV personality tried to grope her, then "humiliated" her.
The BBC has said it is "horrified" by the recent claims but has denied that senior figures knew about Savile's activities and turned a blind eye.
A spokesman said: "We have asked the BBC investigations unit to make direct contact with all the police forces in receipt of allegations and offer to help them investigate these matters and provide full support to any lines of inquiry they wish to pursue."
However its response could come under scrutiny from the public inquiry into media standards.
Anne Main, the Conservative MP for St Albans, has written to Lord Justice Leveson asking him to investigate how the BBC handled the allegations about Savile. The public service broadcaster's Newsnight programme also pulled a programme about Savile on the grounds that it could not stand up the claims made against him.
She wrote: "I have concerns that the public would find it incomprehensible that such serious allegations have only been looked at internally by the BBC."
Philip Davies, who sits on the Culture, Media and Sport committee, said: "The BBC's response to the Jimmy Savile allegations has not been their finest hour. Indeed it bears all the hallmarks of a political scandal where an MP makes denial after denial in a desperate attempt to keep their job - only for the whole house of cards to come crumbling down.
"The new Director General George Entwistle must establish quickly, but thoroughly, exactly who at the BBC was aware of the allegations."