Seven floppy disks labelled top secret which may contain information relevant to the separate loyalist murders of Belfast solicitor Pat Finucane and a high-profile IRA man have been discovered, the High Court has heard.
But a judge was also told that the Ministry of Defence (MoD) is currently unable to access the outdated storage devices.
Details emerged as lawyers for the family of one of the victims accused the security forces of making excuses for failing to properly disclose the material.
His relatives are suing the PSNI and the MoD, claiming informants were linked to the UVF team who carried out the shooting at his home in Ardoyne, north Belfast in April 1987.
Damages are also being sought for alleged misfeasance in public office, negligence, conspiracy to murder and failures in the subsequent police investigation.
The Marley family’s legal action was initially listed for trial in 2023, but has been delayed amid ongoing issues in the discovery process.
At a review hearing on Wednesday, the court was told that the MoD has been carrying out further enquiries about the assessment of seven floppy discs which have now emerged.
The material is understood to be linked to Brian Nelson, who operated as a clandestine British Army spy while an intelligence officer within the UDA.
Nelson is believed to have provided a photograph of Mr Finucane to the loyalist gunmen who shot dead the solicitor in front of his wife and children at their north Belfast home in February 1989.
An independent public inquiry into the killing of the lawyer has been ordered after a number of probes into the case established evidence of state collusion.
Mr Justice Rooney, who is dealing with the Marley family’s case, was informed that the disks “may potentially contain information relevant, not only to these and similar civil proceedings, but to the Finucane Public Inquiry”.
However, a letter from the Crown Solicitor’s Office stated: “MoD has no available hardware, software or expertise to read the disks, as the technology is too old and outdated.”
Although an independent data recovery expert who may be able to access the storage devices has been identified, further concerns were expressed about ensuring any examination does not risk corrupting information contained on them.
According to the letter, there is no index of the disks’ contents.
“The only note available is a handwritten note on each envelope marked ‘Top Secret’ and as such, this cannot be included in open correspondence,” it added.
Stephen Toal KC, representing the Marley family, described the situation as “incredible”.
“It seems the system of discovery is set up for excuses,” he told the court.
Referring to the murder of Mr Finucane, the barrister insisted that the British Government promised full access to all documents on Brian Nelson would be provided for a review carried out by Sir Desmond de Silva back in 2012.
“Some 13 years later seven disks of information relevant to Nelson have emerged and they are labelled top secret,” Mr Toal said.
He claimed the Finucane family were right not to trust what they had been told, and that his clients had no confidence in the discovery process in their case.
“We really require a root and branch exercise to be undertaken,” counsel added.
“It is obvious that Mr Marley’s name was given to the UDA and UVF around the time of his murder, but we need to know if others were in possession of this material… to prove our case.”
Expressing concern at the developments, Mr Justice Rooney said the process does not currently seem to be working and listed a further review next month.
The judge cautioned: “It may well be that I have to interrogate exactly how the MoD looks at discovery.”