Stuart Hall had a room set aside at the BBC where he could entertain "lady friends" while waiting to appear on screen, a former colleague said today.
Linda McDougall, who worked as a producer at BBC Manchester in late 1960s and 1970s, said he had an "amazing set-up" at the BBC building at Piccadilly where the old medical room was reserved for his use.
She said today that the former presenter's activities were widely known about within the organisation.
But Moz Dee, managing editor of 5Live from 1999 to 2008, told the station this afternoon that he had heard no rumours about Hall, which had made today's revelations even more shocking for him.
The BBC said an ongoing search had so far uncovered no written record of complaints "of a sexual nature" being made against the former It's A Knockout presenter.
But a spokeswoman said it would be contacting Lancashire Police to see if any offences had been carried out on its premises.
Ms McDougall told BBC Radio 4's The World At One that Hall occupied the medical room while they were rehearsing for Look North and "he had lady friends who came and went happily on to the BBC premises and kept him occupied during the afternoons".
"I can't say that he was having sex with them there because I wasn't ever in the medical room at the same time but I always thought that they weren't coming for cups of tea at the BBC in the afternoons," she said.
"But of course everyone else knew. We all made jokes about it. You would have had to have your eyes shut and not been at work at all to not know what was going on."
Ms McDougall, who is now a political writer, said she had found Hall "a complete nuisance".
"He was one of those people who had his hands all over you and all over anyone female who came in at any moment he can," she said.
Despite his behaviour, she said they had remained on friendly terms and that she had been shocked to discover that his offences related to children.
"I am shocked, I am really shocked that there were children involved," she said.
"When I found this out this morning I felt really sick and unhappy because I think what on earth was I doing working in a place where this sort of thing is going on."
Hall (83) has admitted indecently assaulting 13 girls, the youngest aged nine.
The sex offences took place between 1967 and 1986.
Mr Dee said he was appalled at the behaviour of the "revered" Hall but said he had heard no rumours.
"Many of us are truly, truly shocked at the scale of the offences, at the fact that he stood in open court and gave the performance of his life... in terms of this denial, only today to admit his guilt," he told the Shelagh Fogarty show.
"When you hear news like that it just, it does knock you and knock your faith in human nature really. It is quite staggering."
He added: "People will be thinking to themselves today 'Was there any clue? Should we have known? Is there anything we could have done?'
"The thing with Stuart Hall is there were no rumours, there didn't seem to be any clues or any suggestion at all that this type of behaviour from him was prevalent."
A BBC spokeswoman said: "According to searches carried out to date, we have uncovered no written record of complaints of a sexual nature being made against Stuart Hall, though our checks are ongoing.
"The police have not shared the details of where these offences took place but we will be discussing the matter with them as soon as possible to see if any further action needs to be taken by the BBC."