The editor of BBC Newsnight, Peter Rippon, has decided 'to step aside with immediate effect' after it emerged that a planned programme celebrating Jimmy Savile was pulled 'for editorial reasons' from the December schedule last year ass allegations of sexual abuse and a police investigation against Savile came to light.

Ahead of a special Panorama programme this evening which will focus on the role of the BBC and the decision to pull the planned programme, the Director General George Entwistle spoke to the press.

Producer Meirion Jones and Reporter Liz Mackean working on the show claim they had interviewed at least four alleged victims of Savile - and confirmed with Surrey Police that officers had investigated sex abuse complaints against the Jim'll Fix It star in 2007. The journalists say that, when they told bosses the Crown Prosecution Service did not charge Savile because of insufficient evidence, they were told to end the investigation - and the show was withdrawn.

However a special edition of Panorama to be shown on BBC One tonight at 9 35 reveals what the BBC and senior managers knew of Savile's decades of child abuse,: why the show was pulled and how BBC director reacted following the explosive 'scoop' documentary by ITV earlier this month.

Written and presented by Ann Salter