MI5 has made an application to withhold information from the inquest of murdered GAA official Sean Brown.
An inquest review hearing on Thursday heard that a Northern Ireland Office (NIO) minister has now issued a Public Immunity Interest (PII) certificate in relation to material provided by The Security Service, which is also known as MI5.
PII certificates are used by state agencies to conceal information they don't want placed in the public domain.
It is understood the PII certificate was signed by NIO minister Steve Baker.
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Mr Brown (61) was attacked and beaten by an LVF gang as he locked the gates at Bellaghy Wolfe Tones GAC, Co Derry in May 1997.
After he was placed in the boot of his own car he was taken to a country lane outside Randalstown, Co Antrim, where he was shot six times.
Collusion is suspected and no-one has ever been charged in connection with the murder.
During yesterday’s hearing, Joseph Aiken KC, counsel for the coroner, Patrick Kinney, confirmed “there is a PII certificate from an NIO minister in respect of The Security Service materials”.
That will now become part of a main PII hearing on a future date.
Later, Des Fahy KC, acting for the Brown family, raised fresh concerns about continued delays on the part of state agencies in providing information to the inquest.
“Our concern remains that the pace at which your team are working is not necessarily being matched by the state agencies,” he said.
He confirmed that the Brown family were only made aware of MI5 attempts to withhold information this week.
“It is of particular concern to me in relation to what we are terming the PII process that yesterday evening (Wednesday) for the first time we were made aware that there is a PII certificate by The Security Service, by MI5, in relation to material that you have already deemed suitable for disclosure,” he said.
“And our concern is that while your team are working and making every effort to have these inquests ready, that obstacles are being placed in the way of the progress of the inquest by the state parties.”
Mr Fahy also expressed surprise that the PII development was only disclosed this week.
“It is a matter of some surprise to us that a certificate dated September 23 was only disclosed to us yesterday and the accompanying concern is that it is inevitably going to add to the PII burden that you have and that you staff have in relation to the dissemination of all material you deem appropriate for the inquest,” he said.
“The next of kin have at all stages recognised the efforts that you are making, your staff are making and that your counsel are making to expedite the preliminaries that are necessary to allow this inquest to begin in January.”
The court also heard that the office of PSNI chief constable Jon Boutcher will also be contacted about the ongoing disclosure work being carried out by the PSNI.
Last month the family of murdered GAA official Sean Brown called on Mr Boutcher to intervene after it emerged that new information disclosed by the PSNI “raises issues in relation” to previous investigations into his killing.
In an interview with the Irish News on Wednesday Mr Boutcher, who was appointed to the PSNI’s top job this week, said the culture within the police of not disclosing information needs to change.
Mr Boutcher also said he “will get to deal with the (Brown) family and make sure that their voice is heard”.
The Brown family's solicitor Niall Murphy, of KRW Law, said: "We appeal to the state parties, the chief constable, the NIO and The Security Service, to listen to the clear direction of the senior coroner today, that they comply with his directions.
"Our sincere concern is that the state parties will filibuster and miss deadlines to avoid compliance, such that this inquest is not concluded by the artificial deadline imposed by the British government to deprive the family of their legal entitlement under the law."
The NIO was contacted.