Black cab rapist John Worboys was cleared for release by the Parole Board because they believe he is now 'open and honest' about his sex offending, the High Court heard today.
The 60-year-old, whose victims are trying to stop his release, has learned 'not to hide negative thoughts and feelings' during 'positive' treatment with psychologists over the past ten years.
Worboys, who is one of Britain's most notorious sex offenders, has admitted attacking between 20 and 25 women after 2005 in his black cab where police found a rape kit of alcohol and drugs.
But a QC representing two of those victims said today 105 women have been identified by police since 2002 proving that Worboys 'doesn't have full acceptance of his guilt' and should remain behind bars.
Phillippa Kaufmann told the High Court: 'It blows out of the water the Parole Board's finding that he is open and honest.'
The women trying to stop his release, who cannot be named, claim he remains a dangerous sexual predator and believe the parole board's decision to free him is 'irrational' and 'wrong'.
The appeal hearing is set to last two days and a grey and haggard Worboys watched via video link from prison.
The 60-year-old former stripper and adult film star-turned-cabbie was jailed indefinitely in 2009, with a minimum term of eight years, after being found guilty of attacks on 12 women over 18 months involving rape, assaults and drugging.
Police believe that Worboys, who now calls himself John Radford, may have attacked more than 500 passengers and 102 women reported him to detectives. He was only prosecuted over a dozen victims because officers did not want to 'overload the indictment', the court heard today.
But in January the Parole Board announced he would be released on licence after less than a decade behind bars, despite warnings that he could still pose a risk to women.
One of the victims bringing the challenge is present in the packed courtroom.
The three judges hearing the case have heard that Worboys denies committing any offences other than those he was convicted of.
Today two victims and the Mayor of London Sadiq Khan begin their challenge to the decision in January saying it is 'irrational' that he no longer poses any threat to the public.
Worboys appeared via video link from prison for the latest hearing concerning his potential release.
Lawyers for victims argue that 'something went badly awry' at the Parole Board as crucial evidence was ignored and board members made an 'irrational' decision.
Phillippa Kaufmann, QC, on behalf of the victims said: 'This is a case where the parole process has gone badly wrong.
'It is submitted that the decision was unlawful on two main bases.
'First because the board failed to take into account evidence... second because even putting aside that crucial failure, the decision was irrational.' She wants the High Court to declare the Parole Board decision is unlawful and order that the board reverse its decision or at least agree to reconsider it'.
Ms Kaufmann told the court the Parole Board's reasons for believing Worboys no longer poses a risk to society included that he had 'learned to be open and honest'.
She said the board also considered his risk was reduced because of the fact he took 'full responsibility' for his crimes, had 'good insight' into his behaviour and had undergone treatment.
However, the barrister said police who investigated Worboys believed he had committed offences against 105 women.
She added that he often left victims 'confused and disoriented' and with only a partial memory of their ordeal.
Ms Kaufmann told the court both victims bringing the case against him were found to have traces of sleeping tablets in their blood.
Ms Kaufmann said the wider allegations against Worboys 'completely undermined' the board's reasoning.
She told the court: 'It is obvious, absolutely obvious, that this evidence of wider offending had a central bearing on all of those conclusions that formed the basis of the Parole Board's conclusion that there had been a reduction in risk.'
She said Worboys' account that the 'trigger' for his offending was the end of his relationship in 2005, when police believed his crimes started two years earlier.
She added: 'That throws into question the entire account that he has given for why his offending began.
'Hence the finding that he had insight into his offending is simply blown out of the water.
'It also blows out of the water the Parole Board's finding that he is open and honest.'
As the case got under way, London Mayor Sadiq Khan said in a statement that it was his 'top priority to keep Londoners safe'.
He said: 'I am morally and duty-bound to do everything within my power to protect them from harm.
'John Worboys presents a significant threat to Londoners' safety and on behalf of his victims and survivors, I felt I had to be involved.'
He added: 'Many of John Worboys's victims live and work in London. I have been clear that he shouldn't be released at the very least until the decision has been properly independently scrutinised and we are reassured that those in positions of power and responsibility are doing everything they can to keep all his victims, and the rest of us, safe.'
It is said Worboys, who has changed his name to John Radford, does not oppose the reasons for his freedom being granted being made public.
But he is seeking restrictions on his whereabouts and the address of any rehabilitation project he has to participate in.
At an earlier hearing the 60-year-old was photographed being led into the Royal Courts of Justice in London, almost a decade after he first appeared before magistrates in February 2008.
Worboys appeared grey and haggard as he sat in a caged dock of the Royal Courts of Justice.
He was driven 185 miles to London from his cell at Wakefield Prison in Yorkshire at the expense of taxpayers after a judge ordered he attend in person.
Two of his victims were also in court, and that at least one of them objected to coming face to face with him for the first time in a decade.
Worboys was ordered to stay in jail for a minimum term of eight years after being convicted of 19 offences against 12 victims.
The Crown Prosecution Service only proceeded with 14 cases and did not haul him back to court when more victims came forward after his 2009 trial as it was assumed he would be locked up for the rest of his life after being given an indeterminate sentence for public protection (IPP).