Police have agreed to hand over nearly 40 folders of documents for a legal action over the SAS killings of eight IRA men, the High Court heard.
But a further five sensitive dossiers on the Loughgall ambush are to be examined by the Chief Constable amid steps to secure Public Interest Immunity over some contents.
The developments came in a lawsuit brought by the father of one of those shot dead in the Co Armagh village in May 1987.
Undercover soldiers targeted the IRA East Tyrone unit as they approached an RUC station with a bomb in a hijacked digger.
Eight IRA terrorists died along with an innocent civilian, Anthony Hughes, who was caught up in the gunfire.
Relatives of those killed claim soldiers operated a deliberate shoot-to-kill policy.
Declan Arthurs’ father, Patrick, initially sued just the Ministry of Defence over the ambush but this was later extended to the PSNI.
Last year a judge declined an attempt to have the police defence to Mr Arthur’s action dismissed for failing to hand over requested documents.
At that stage an Assistant Chief Constable stated that the discovery process would involve searches of electronic, microfiche and hard copy material in stores holding more than 9.5 million intelligence records.
The Crown Solicitor’s Office has now confirmed that 39 folders of non-sensitive documents have been assembled.
The court was told that all of these dossiers will be made available to Mr Arthurs’ lawyers at the end of this month.
Tony McGleenan QC, for the Chief Constable, said: “That will provide the plaintiff with a very sizeable volume of material to examine.”
He also revealed that another five folders containing sensitive information is expected to be subject to a PII claim.
The process of editing and redacting would involve a certificate being issued by the Secretary of State or another Northern Ireland Office minister by the end of July, Mr Justice Deeny was told.
He directed that all sensitive files are to be forwarded to the Secretary of State, if the Chief Constable seeks PII, as soon as possible.
Outside court Mr Arthurs’ solicitor lamented the delay in securing the material.