Two victims of black cab rapist John Worboys are to ask leading judges for the go-ahead to challenge the decision to release him from prison.
At the same hearing at the High Court, London Mayor Sadiq Khan will also urge Sir Brian Leveson and Mr Justice Garnham to allow him to bring judicial review action against the Parole Board.
Another senior judge has already temporarily blocked the 60-year-old serial sex attacker's release pending the hearing in London on Wednesday, which is due to last half a day.
On January 26, Mr Justice Supperstone made his decision after considering an urgent application by two of Worboys' victims.
The women, supported by Mr Khan, applied for a "stay" on Worboys' release "pending determination of the claim for judicial review or further order".
Sir Brian and Mr Justice Garnham will consider applications by the women and the mayor, and if permission is granted a full hearing will take place at a date to be fixed.
If the cases are allowed to proceed, it is likely that the judges will also be asked to decide on whether the current bar on release should be extended.
In making his order in January, High Court judge Mr Justice Supperstone, who considered the application on documents lodged by the parties, concluded: "I consider that this claim raises serious questions to be determined and the balance of convenience plainly favours a short stay pending the hearing."
He said the judicial review claims brought by the two women, who cannot be identified for legal reasons, and Mr Khan "shall be linked".
The judge stated that the release of Worboys "pursuant to the decision of the Parole Board for England and Wales directing his release shall be stayed pending the hearing on permission for judicial review and directions... or further order".
Worboys was jailed indefinitely in 2009, with a minimum term of eight years, for drugging and sexually assaulting women passengers.
He became known as the black cab rapist after attacking victims in his hackney carriage.