Black cab rapist John Worboys has been handed two life sentences with a minimum term of six years for attacking four more women.
The 62-year-old, who is now known as John Radford, was jailed in 2009 for assaults on 12 women in London.
The four victims came forward after the public outcry caused by the parole board ruling he was safe to be freed.
Sentencing Worboys, Mrs Justice McGowan said she did not know when “if ever you will cease to be a risk”.
In 2009, Worboys was locked up indefinitely for the public protection with a minimum of eight years after being found guilty of 19 sex offences against 12 women between 2006 and 2008.
Last year, the Parole Board overturned a decision to release him and ruled that he should remain in prison, citing his “sense of sexual entitlement”.
Prosecutor Duncan Penny QC told the Old Bailey that psychiatrist Philip Joseph found Worboys had been “fantasising” about attacking women since 1986.
A probation report in August this year found “he is potentially just as dangerous now as the point of the first sentence”.
After the four women came forward, Worboys, of Enfield, admitted two charges of administering a drug with intent to commit rape or indecent assault.
He also pleaded guilty to two further charges of administering a substance with intent to commit a sexual offence.
Mr Penny said the first victim was targeted in 2000 or early 2001 after a night out at a wine bar in Dover Street in Soho.
The second victim, a university student living in north London, was picked up after a night out with friends at a club on New Oxford Street in 2003.
Worboys’ third victim was picked up after a night out on King’s Road in 2007 where he told her he had won £40,000 at a casino and offered her champagne.
The court heard Worboys told the fourth victim he had won the lottery and offered her and her friend miniature bottles of champagne.
Mr Penny said: “She woke up in bed the following morning. The bedclothes had not moved and her hands were crossed over her chest, which was unusual.
“She was sufficiently unnerved to check herself. There were no visible signs she had been touched.”
Mr Penny told the court: “The consistent themes throughout, together with the content of what took place, seems to be the profound effect not knowing what happened has had in each of these women throughout their lives, as a result of having been unfortunate enough to get into the defendant’s black cab.”
Police believe Worboys may have carried out more than 100 rapes and sexual assaults on women in London.
Becki Houlston, who has waived her right to anonymity, said Worboys drugged her in Bournemouth.
“He was pretty pre-meditated from the get-go, and I was a woman on my own,” she told the BBC.
“He is highly manipulative and relentless. It becomes easier to just accept a drink to shut him up.”
In Ms Houlston’s case, the Crown Prosecution Service (CPS) said there was not enough evidence to prosecute.
Reacting to the sentencing, the CPS’s Tina Dempster said: “John Worboys is a dangerous predator who still poses a clear threat to women.”