Victims of John Worboys came face-to-face with the serial rapist at a court hearing, as they were granted permission for a legal challenge against the decision to release him from prison.
The former black-cab driver will remain in prison pending a full hearing in mid-March.
The case was brought by two victims, supported by London Mayor Sadiq Khan, who say the rapist remains a threat and should not be released.
"The victims of John Worboys, and all Londoners, will be relieved at this ruling," Mr Khan said, after the ruling.
Worboys, dressed in grey and flanked by security guards, arrived at court from Wakefield Prison to hear whether or not the Parole Board's controversial decision to release him should be overturned.
He was ordered to appear in person after technical problems with the video link. Lawyers for the victims said they were unhappy at seeing their attacker in person.
Worboys was jailed indefinitely in 2009, with a minimum term of eight years, for drugging and sexually assaulting women passengers.
The Parole Board's decision to release Worboys, announced last month, was met by widespread condemnation from victims and Parliament.
Earlier on Wednesday, a government-ordered review found that Worboys' victims were "shocked and distressed" to find out about his release in the media.