London Mayor Sadiq Khan has said the Parole Board must reconsider their decision to release John Worboys, the so-called 'black cab rapist' who served just eight years in jail.
London cabbie Worboys, a former stripper and adult film star, was jailed indefinitely in 2009, with a minimum term of eight years, for drugging and sexually assaulting female passengers.
Worboys, who became known as the "black cab rapist", was found guilty of 19 charges of drugging and sexually assaulting 12 women passengers, in one case raping a woman.
But police said in 2010 that his alleged victims actually numbered 102, after more people came forward following his trial and conviction. The allegations were investigated but no further action was taken on the advice of the Crown Prosecution Service (CPS), police said.
Khan's declaration comes after the chair of the Parole Board has apologised "unreservedly" over the failure to inform Worboys' victims of his imminent release.
Professor Nick Hardwick said he fully accepts there was a problem with the parole system, and that it was believed the victims had been informed before the decision was issued.
Hardwick told the BBC he is still trying to establish precisely what happened and does not want to "blame anybody yet."
He said it was not the Parole Board's responsibility to inform victims, and added: "Whoever's fault it was, I fully accept this was a problem with [the] parole system.
"I'm chair of the Parole Board, this would have been absolutely horrible for those two women concerned, and I apologise for it unreservedly."
In a statement, Hardwick said he has "recently set out options for change" and that the Parole Board has a "statutory duty" under its rules which "prevents disclosure of proceedings."
"We will shortly be launching a public consultation about how we share our decision-making with the public," he added.
Lawyer Harriet Wistrich claimed two victims had not been informed of Worboys' imminent release or of his Parole Board hearing.
She said they are both "shocked and horrified by this news", and told Channel 4 News that the first they learned of the planned release was while "listening on the radio, cooking tea for the kids."
It is understood that all those who were signed up to the Victim Contact Scheme were informed as soon as the Parole Board decision was made.
Yvette Cooper, chairwoman of the Home Affairs Select Committee, has called for the Parole Board to immediately publish its reasons for allowing the release of Worboys.