The inquiry into alleged child abuse by Jimmy Savile is now a formal criminal investigation involving other living people, Scotland Yard said.

Operation Yewtree has moved from an assessment to a criminal investigation after detectives established there are lines of inquiry involving ‘living people that require formal investigation’. Scotland Yard said two weeks of gathering information has involved assessing more than 400 lines of inquiry and has identified more than 200 potential victims.

The force said: “As we have said from the outset, our work was never going to take us into a police investigation into Jimmy Savile. What we have established in the last two weeks is that there are lines of inquiry involving living people that require formal investigation.”

Operation Yewtree, originally an ‘assessment’ into claims against Savile, was launched after allegations flooded in following an ITV documentary screened earlier this month.

On Friday the NSPCC said it is possible the former Top Of The Pops presenter was ‘one of the most prolific sex offenders’ the charity has ever come across.

Claims have also emerged about fellow entertainers Freddie Starr, who has staunchly refuted the allegations, as well as Gary Glitter – real name Paul Gadd.

As well as police investigations, inquiries are taking place into Savile’s involvement with Stoke Mandeville Hospital, Broadmoor and Leeds General Infirmary.

Dame Janet Smith, who headed the Shipman Inquiry, has been appointed to head an inquiry into Savile’s time at the BBC and Scotland Yard said they recognised ‘her need to progress this important work’.

It has also emerged that the BBC is aiming to rush a special edition of Panorama into its schedules looking into issues surrounding Jimmy Savile’s years of abuse, which could be run on Monday.

Commander Peter Spindler, from Scotland Yard, said: “The public’s response to this issue has been astounding. We are dealing with alleged abuse on an unprecedented scale. The profile of this operation has empowered a staggering number of victims to come forward to report the sexual exploitation which occurred during their childhood.”