Savile possibly 'one of the most prolific sex offenders' ever

Police will pursue 400 lines of inquiry Credit: Press Association

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

Operation Yewtree has been moved to a criminal investigation after officers established more than 400 lines of inquiry and identified more than 200 potential victims.

Scotland Yard said there are lines of inquiry involving "living people that require formal identification."

Commander Peter Spindler said the scale of alleged abuse was "unprecedented" and involved a "staggering number of victims"

The NSPCC said it was possible the late BBC presenter was "one of the most prolific sex offenders" the charity had ever seen. Peter Watt, head of the NSPCC's helpline said: