Highly-classified documents will be included in the published report of a Government-ordered review into the murder of Belfast solicitor Pat Finucane.
Sir Desmond de Silva QC, the barrister who led the inquiry, said the disclosure was being made to ensure public confidence.
He said: "The inclusion of a volume of normally highly classified documents is clearly an exceptional step for a review such as this to take.
"I decided that it was necessary to include these documents in view of the controversy surrounding this case and to ensure public confidence in my report."
The £1.5 million review is due to be published the week beginning December 10.
Mr Finucane was gunned down in his north Belfast home by loyalist paramilitaries in 1989. The murder of the Catholic father of three was one of the most controversial of the Northern Ireland Troubles, with allegations the state colluded to facilitate the killing.
Prime Minister David Cameron has accepted collusion took place and has apologised to the Finucane family.
But his refusal to hold a full public inquiry into the murder - instead opting for the legal review - angered the high-profile solicitor's relatives, who subsequently launched a bid to challenge the decision in the courts.
There is nothing in the de Silva report to endanger the lives of individuals or put national security at risk, Northern Ireland Secretary Theresa Villiers said today.
Sir Desmond added: "In view of the history of delays in independent reviews or inquiries such as this, I am pleased to say that my report has been produced on time and on budget."
Ms de Villiers said the report has not been shown to her or any other member of the Government or officials, except the members of the checking team.
The Northern Ireland Secretary stated that, as with the publication of earlier reports like the Bloody Sunday Inquiry, she intended to give advance sight to interested parties, their legal representatives and some members of both houses of Parliament.
The Finucane family reiterated their call tonight for a full public inquiry into the murder.
Mr Finucane's widow Geraldine said: "My family and I remain committed to achieving our goal of an independent public inquiry into all of the circumstances surrounding Pat's murder.
"Our case for an inquiry has become even stronger following the admission by the British Government that there was state collusion in my husband's killing. This makes their refusal to honour the commitment to hold an inquiry even more disgraceful.
"The Secretary of State makes much of her Government's anxiousness to publish the de Silva report in full, as if this were some sort of guarantee of openness and transparency.
"In reality, it is nothing of the sort."
She insisted the review would not contain "vital information" relating to the murder.
"By the time the report is made public, it will have been sanitised completely, to ensure that the least possible amount of discomfort is caused to the Government and the British State," she added.