How was the taxi rapist able to strike so many times?

Police believe John Worboys may have attacked hundreds of women in 13 years as black cab driver

Evidence gathered during the case against Worboys ( PA)

The case of John Worboys, the taxi rapist, has prompted the Liberal Democrats to demand high-level meetings with the Metropolitan Police Commissioner Sir Paul Stephenson and the Association of Chief Police Officers tomorrow.

Simon Hughes, the Liberal Democrat MP for North Southwark and Bermondsey, will ask why Worboys, who was convicted last week of a string of sex attacks on women he drugged and assaulted in his cab, committed a series of crimes that need never have happened.

Although Worboys was arrested in July 2007 on suspicion of the sexual assault of a 19-year-old woman, detectives did not forward the 2007 case to the Crown Prosecution Service (CPS) and he was freed. He went on to attack at least six women before he was arrested for a second time last February and finally convicted of a number of sex offences on Friday.

The police and the CPS need to "sharpen up their detection and prosecution work if they are to catch repeat serious offenders like Worboys at an earlier stage", according to the MP.

This week will see the Independent Police Complaints Commission begin a review of the police investigation into the July 2007 arrest.

"After Harold Shipman and Ian Huntley, the John Worboys case shows there are clearly still failings to detect early serial offenders who abuse positions of responsibility when the public is in vulnerable situations," he said. "The public needs to know how Worboys, like others, got away with so much evil behaviour for so long. The young and old and others in vulnerable positions must know that criminal behaviour by those they trust ... will be picked up and acted on as soon as the first alarm bells ring," he added.

Worboys was found guilty of drugging and sexually assaulting a series of female passengers in the back of his cab. The 51-year-old from Rotherhithe, London, picked up his lone victims in London's West End and plied them with drinks laced with sedatives, Croydon Crown Court heard.

The former male stripper turned cabbie, who will be sentenced next month, was convicted of one rape, five sexual assaults, one attempted assault and 12 drugging charges, committed from July 2007 to February 2008.

But police believe he attacked more than 200 women during his 13 years as a licensed taxi driver, and say they have already identified 85 victims.

Specialist officers from the Met's Sapphire unit, which deals with rape cases, were manning a special police hotline for other victims of Worboys to come forward.

The Met refused to specify numbers, but it is understood the phone line has been inundated with calls. A police spokesman said: "It is unusual to have a hotline for a specific case, but this is a very serious case with the potential for more victims."

Yesterday Jean Clayton, Worboys's former wife, claimed that he had spied on her teenage daughters from a previous relationship and preyed on vulnerable women during their marriage. Ms Clayton, who separated from Worboys in 1995, said that he had confessed to being a sex addict and to following a drunk woman home and sexually assaulting her.

Bob Oddy, general secretary of the Licensed Taxi Drivers' Association, offered reassurance yesterday. "We carry a quarter of a million passengers in London every day. I'm confident that every one of these passengers will have a safe journey, particularly now Worboys has been taken off the streets."

He added: "We are appalled at this guy's behaviour and obviously want to extend our sympathy to all the victims and families.

"We're offering £10,000 to St Mary's Hospital's rape haven in Paddington, one of three centres in London that assist victims of rape and sexual harassment. We understand some of the victims were helped there."

A criminal history

14 October 2006

A woman aged 25 accepts the offer of a drink and wakes up to find Worboys assaulting her.

26 July 2007

A 19-year-old student is forced to take a pill after she is persuaded to have a glass of champagne. She wakes with blood in her underwear but has no memories of the night.

27 July 2007

Worboys is arrested after CCTV shows him carrying the teenager out of his cab. The case is eventually abandoned and not passed to CPS.

16 February 2008

Arrested by police, following several attacks on women.

18 February 2008

Charges brought against Worboys include one count of rape, four of sexual assault and six of administering a substance with intent.

January 2009

Worboys denies 23 charges at the start of his trial.

13 March 2009

Found guilty of one rape, five sexual assaults, one attempted assault and 12 drugging charges.