All material seized from two Belfast journalists during police raids on their homes and offices should be handed back, High Court judges said.
With search warrants obtained to carry out the raids quashed, Mr Birney and McCaffrey are pressing for the return of millions of documents, computer equipment and phones by earlier next week.
Lord Chief Justice Sir Declan Morgan insisted they had acted properly by protecting their sources.
He gave police until Monday to explain their claims it will now take up to a fortnight to retrieve and return everything taken.
"I can't see that this would be an extremely arduous thing to do," Sir Declan said.
Amid the uncertainty over when the handover will take place, pledges were given that detectives will carry out no further examinations of the seized material.
Lawyers for Mr Birney and Mr McCaffrey also gave undertakings that none of the material will be destroyed for 28 days after its return.
The assurance gives police an opportunity to seek a court order for the production of any specified items.
"They will retain the materials secure, intact and available for production in accordance with production order made under Schedule 1 of PACE (Police and Criminal Evidence Act).
Earlier this week the journalists won their challenge to the legality of warrants granted as part of an investigation into the alleged theft of confidential documents from the Northern Ireland Police Ombudsman's Office.
The case is connected to a documentary film examining the loyalist murders of six Catholic men at Loughinisland, Co Down in June 1994.
On Wednesday the court held that authorisation for the searches which led to the arrest of Mr Birney and Mr McCaffrey had been inappropriate.
Returning to the case on Friday to deal with the issue of remedies, Sir Declan set out further reasons why the warrants were legally flawed.
He said it had been unclear what potential offence was being investigated under the Official Secrets Act.
It was also stressed how Mr Birney and Mr McCaffrey had acted in accordance with the National Union of Journalists code.
"There was no evidence adduced which persuaded us the journalists were acting in anything other than a perfectly appropriate way, with a view to doing what the NUJ requires them to do, which is to protect their sources," Sir Declan said.
"We consider that there's no reason why, subject to suitable protections, for declining to return the material in their entirety to the journalists."
A final order setting out a deadline for the handover is expected to be drawn up following a further hearing on Monday.
The award-winning investigative journalists were involved in the documentary film No Stone Unturned, which scrutinised the Royal Ulster Constabulary's handling of the Loughinisland atrocity.
In August last year they were detained, questioned and released during an operation undertaken by detectives from Durham Constabulary, supported by PSNI officers.
Judicial review proceedings were brought in a bid to have the warrants declared unlawful.
During the hearing lawyers for Mr Birney and Mr McCaffrey contended that the search operation was aimed at discovering sources and intimidating whistleblowers.
Judges were told the raids were told the raids were an "outrage" more akin to a police state than a liberal democracy.
During the hearing counsel for the police raised issues around any potential appeal to the judgment.
In a statement issued later, Durham Constabulary Chief Constable Mike Barton said: "We followed due process when applying for the search warrants. A detailed application was presented to a County Court judge who granted the warrants.
"We respect the outcome of today's hearing and the judge's decision, and we will consider its implications."
It was confirmed that Mr Barton will accompany PSNI Chief Constable George Hamilton at next week's meeting of the Northern Ireland Policing Board.