Two newspapers have threatened legal action if the Parole Board does not publish its reasons for agreeing to release convicted rapist John Worboys.
If they do not release it within seven days, the papers have said they will apply for a judicial review.
Both the board and Ministry of Justice said they are legally prohibited from disclosing Parole Board decisions.
Former black-cab driver Worboys, 60, was jailed for a minimum term of eight years in 2009 for drugging and sexually assaulting women passengers.
After a hearing about his case in November, the Parole Board decided to approve his release with “stringent” licence conditions.
The decision was met with a furore by Worboys’ victims and in Parliament.
On Tuesday Scotland Yard confirmed it is investigating a new allegation of sexual assault made against him this month – though dating back to 1997 – which could delay his release date if it leads to criminal charges.
No arrests have been made.
What is a judicial review?
A judicial review is where a judge reviews the lawfulness of a decision made by a public body – in this case, the Parole Board.
It is less about whether the decision was right or wrong, and more about challenging whether proper procedures were followed to reach the decision.
The Sun said the “secretive system” of the Parole Board should end, adding that the report on Worboys’ release was “integral to the debate on a matter of profound public interest” where there was “overwhelming public concern”.
The Daily Mail said Worboys’ offences crimes were of such “severity” that “normal rules should be set aside”.
Two women – a victim and a second woman who says Worboys attacked her in 2003, although her complaints never reached court – have already threatened to launch a judicial review.
The government had been considering the possibility of a legal challenge to Worboys’s release, but Mr Gauke told the House of Commons that, after consulting lawyers, it would not be appropriate to proceed.
However, Prime Minister Theresa May confirmed there would be a review into the way parole is considered.
Both the Parole Board and the MoJ said they were legally prohibited from disclosing Parole Board decisions or evidence and they backed the review already announced.