BBC director-general George Entwistle has asked a senior colleague to answer journalists' questions on the dropping of a documentary about Sir Jimmy Savile.

Ken MacQuarrie, director of BBC Scotland, will speak to Newsnight journalists about the aborted broadcast after several of them wrote to Mr Entwistle to ask why the film was not aired, a BBC spokesman confirmed.

The director-general asked Mr MacQuarrie as he was a "senior member of management" at the BBC, the spokesman added.

The BBC's reputation is increasingly under fire after an avalanche of allegations that the corporation was aware of claims about Savile's actions, but did nothing about them.

David Nicolson, who worked as a director on Jim'll Fix It, claimed to have caught Savile having sex with a girl in his dressing room, but was laughed away when he voiced his concerns, The Sun said.

Grant Shapps, chairman of the Conservative Party, told BBC One's Question Time on Thursday night that it "seems unimaginable" that people at the BBC were unaware of the child abuse allegations.

He said: "What happened now appears to be outrageous. It's particularly disturbing that a programme paying tribute, a three-parter, went out just last Christmas after it was already known at senior levels within the BBC that something was wrong, enough to have had a serious Newsnight programme made about it and enough to raise serious concerns. I do think there are definitely questions that do need answering."

Mr Shapps backed calls for Savile to be stripped of his knighthood, saying "it can't be right" that he remains a Sir in name following the allegations.

Fresh claims of sexual abuse have been made against the late TV presenter, following allegations that he preyed on children during hospital visits.

A string of police forces have received complaints and referred them to Scotland Yard, which is leading the investigation. Greater Manchester, Lancashire, North Yorkshire and Tayside are the latest forces to say allegations have been made.