Mr Justice Colton also rejected claims the PSNI should not have to hand over more files to a man who survived two UVF assassination bids because the process could take years and cost hundreds of thousands of pounds.
He ruled there was potentially further documentation in the possession of the force that should be provided to John Flynn’s legal representatives.
Mr Flynn, from north Belfast, is suing the police over two attempts on his life allegedly carried out by an agent who operated in the city’s Mount Vernon area.
In 1992 a gunman tried to shoot him after he was lured to Whiteabbey Hospital on the outskirts of the city.
Five years later a second attempt was made to kill him in a failed car bomb attack.
The 56-year-old issued proceedings against the PSNI for alleged negligence and misfeasance in public office.
It was confirmed last year that the PSNI has admitted his misfeasance claim and accepted he should be paid damages which could ultimately reach £75,000.
But the force emphatically denies negligence or having ever employed the agent - identified only in the case as ‘Informant 1’.
He is suspected of involvement in 10-15 murders, punishment shootings, serious beatings, conspiracy to murder, robbery, hijacking and drug dealing.
Mr Flynn’s action was triggered by the findings of Police Ombudsman Nuala O’Loan that some Special Branch officers colluded with loyalist killers.
Her Operation Ballast report, issued back in 2007, centred on the activities of a UVF gang allegedly led by Mount Vernon man Mark Haddock.
As part of the lawsuit Mr Flynn’s lawyers sought access to 94 categories of documents.
In court they argued that the police admission of partial liability was a tactical move to avoid handing over all files on the informant and cover over the full extent of alleged collusion.
An affidavit filed by Mr Flynn claimed police either failed to arrest the agent for the murders and other crimes or else conducted “sham” interviews, despite knowing he was a leading UVF figure.
Misleading records were deliberately compiled, while other documents and forensic exhibits were either destroyed or lost, he alleged.
Mr Flynn also claimed: “I believe that the police knew I was at risk from Informant 1 and were quite content to let me be murdered by him and his associates.”
Counsel for the Chief Constable argued that it was disproportionate and unnecessary to try to gain access to a “vast” amount of documentation when an admission of liability has been made.
He revealed that the material being sought covers a period of up to 14 years.
The court also heard it would take an estimated two years to identify all the documents and comply with the level of discovery being sought.
A Public Interest Immunity (PII) process alone would cost in excess of £300,000, according to a Superintendent asked to assess the scale.
But Mr Justice Colton said on Friday: “In a case such as this, given the grave allegations that have been made against the agents of the state, resource arguments are unattractive.”
Despite accepting that an order for specific disclosure may be laborious and time consuming, he added: “There is a force in the plaintiff’s submission that the defendant has not taken its discovery obligations seriously, at least prior to the admission defence.”
According to the judge much of the requested files should be already available because it featured in the Ballast report.
“I simply cannot understand why that material cannot be identified,” he said.
“Accordingly, I have come to the conclusion that the list of documents served in this action does not comply with the defendant’s obligations.”
With potentially more material held to be in the police possession that should be handed over, Mr Justice Colton directed further submissions which may lead to a “bespoke” discovery process being devised.
Outside court Mr Flynn’s solicitor pledged to take steps to ensure full and urgent disclosure.
Claire McKeegan of KRW Law said: “The PSNI have tried at every turn to avoid disclosing any relevant material to allow us to resolve this case.
“This decision is important not only to the matter at hand but to all of our legacy litigation where the state representatives have cited resources as justification for non-compliance with the rules.
“We see today’s decision as a marker that this position will not be accepted.”