An unnamed celebrity who was arrested this week as part of investigations into sexual assault claims against Jimmy Savile has told friends the experience has left him "in excruciating agony".

The man, who is 82 and lives in Berkshire, was questioned for around 10 hours on Thursday 28 March over allegations of sexual assault.

The star's identity has not been released by police, and he has yet to be named in the media.

It is the second time he has been questioned by officers from Operation Yewtree, the investigation into claims of sexual abuse by Jimmy Savile and others, after he was first brought in for questioning last November.

"This is destroying him. He is in excruciating agony and at his wits' end," a friend of the star told the Daily Mirror.

"He cannot understand why he has been arrested. He is a private man and is tormented by what's happened. He is shocked and distressed and cannot understand why he's been arrested.

"He's trying to get on with his life but finding it really, really quite impossible to think straight. My friend is a lovely, loyal devoted husband and father and I can't imagine him ever doing anything to tarnish his rightfully earned image."

The celebrity was arrested after voluntarily attending a police station by prior arrangement with his solicitors, Harbottle & Lewis. He was released at midnight on Thursday.

It was not known whether he had returned to his gated Berkshire home, where curtains remained drawn yesterday, or whether he was staying with friends. The occupants of the property declined to comment on the allegations.

The suspect is the eleventh person to be arrested as part of Operation Yewtree. Others have included PR consultant Max Clifford, comedian Freddie Starr, DJ Dave Lee Travis, singer Gary Glitter, producer Ted Beeston and TV comic Jim Davidson.

He was originally interviewed under caution on 29 November, five days after a search warrant was executed at his home. He has been bailed to reappear in May.

Senior lawyers have been advising the police on the case, according to a spokesman for the Crown Prosecution Service.

"The CPS has given investigative advice to police in relation to a man in his eighties from Berkshire in relation to possible offences of a sexual nature," said the spokesman.

Operation Yewtree was established to investigate allegations of sexual abuse surrounding Jimmy Savile and others. The 82-year-old suspect was arrested as part of the "others" strand of the investigation, dealing with allegations unrelated to Savile.

The star has been named on a number of internet sites.

Another suspect, the former BBC producer Wilfred De'ath, was this week informed he will not face charges after a woman withdrew her allegations against him.

Tory Peer Lord McAlpine accepted £185,000 from the BBC and £125,000 from ITV after he was wrongly implicated in sex assault allegations last November.