Radio and TV presenter Dave Lee Travis was reportedly arrested on Thursday as part of the police investigation set up in the wake of allegations against his BBC colleague Jimmy Savile.
Police said a man in his 60s was being held on suspicion of sexual offences, although they did not officially name him.
But media widely reported that Travis, 67, was being questioned by detectives.
Travis, nicknamed the Hairy Cornflake, worked with Savile at BBC Radio 1 during the 1970s and 1980s and was one of the most recognisable faces in British broadcasting.
Last year Myanmar's pro-democracy leader Aung San Suu Kyi said his World Service music request show had helped her to get through more than two decades under house arrest.
Travis met Suu Kyi when she visited BBC studios during a visit to Britain in June.
There is no suggestion that any accusations of paedophilia have been made against him, although two women have alleged in recent weeks that he groped them in the 1970s. He strongly denied the allegations when they were made.
Savile, one of the BBC's biggest stars for more than two decades, is believed to have preyed on under-age girls, sometimes on BBC premises.
Police said Thursday the number of victims in the Savile investigation has risen to 450 from the figure of 300 it gave last month.
Although the vast majority of allegations are against the eccentric presenter, who died last year at the age of 84, the Scotland Yard probe has widened to include other figures in the entertainment industry.
Former glam rock star and convicted paedophile Gary Glitter, comedian Freddie Starr and a 73-year-old man have been arrested and bailed in connection with the investigation.
Meanwhile, the BBC said on Thursday it would reach a settlement with a senior politician whom it implicated in child sex abuse allegations.
Lord Alistair McAlpine said in an interview that the BBC could have saved "a lot of agonising and money" by simply contacting him before showing a TV report implicating him in a paedophile ring at a children's home in Wales.
A BBC spokeswoman said: "The BBC is hopeful that it can agree a settlement with Lord McAlpine today."
The broadcaster has already apologised for linking McAlpine, who was Conservative party treasurer during Margaret Thatcher's era, with abuse at a children's home in Wrexham in Wales in the 1970s.
The report broadcast by the BBC's flagship current affairs show Newsnight did not name him but he was quickly identified on social networking sites.
The false allegations, coming as the BBC was under intense scrutiny over its decision to spike a report about child abuse claims surrounding Savile, plunged the world's largest broadcaster into one of the worst crises in its history.
BBC director-general George Entwistle has resigned over the report, while two other top executives have also stood aside.
McAlpine said Thursday in an interview with BBC radio he had been "in a state of shock" after he heard of the allegations.
"To suddenly find I was mixed up in all this -- and I didn't know what Newsnight was going to say -- it really was a horrendous shock.
"Of course they should have called me and I would have told them exactly what they learnt later on.
"That it was complete rubbish and that I'd only ever been to Wrexham once in my life."
It emerged that an abuse victim who had implicated McAlpine in the Newsnight report had not been shown a photograph of him.
Only after the report was broadcast did he realise McAlpine was not the man who had assaulted him.
McAlpine's lawyer Andrew Reid said that legal letters would be sent to individuals who mentioned the peer's name on the Internet, particularly Twitter.
Britain's broadcasting watchdog Ofcom said it was investigating the programme, and was also looking into a presenter from the ITV station after he brandished a list of alleged abusers he had gathered from the Internet and handed it to Prime Minister David Cameron during a live interview.
ITV said it had taken "appropriate disciplinary action" over the incident last week in which presenter Phillip Schofield asked Cameron if he would investigate the names.