A report on the review into the murder of solicitor Pat Finucane runs to 500 pages, it has been revealed.
Another 500 pages of supporting documents will be published at the same time next month, said the Northern Ireland Office.
Northern Ireland Secretary Theresa Villiers will receive a copy of the report the previous day.
Father-of-three Mr Finucane, 38, was shot dead when loyalist UDA/UFF gunmen used sledgehammers to burst in through the front door of his home in north Belfast in February 1989.
Mr Cameron has accepted collusion took place and has apologised to the Finucane family.
But Mr Finucane's widow Geraldine and relatives have been critical of the £1.5 million review ordered by the Prime Minister, claiming it falls short of the full public inquiry they demanded.
Sir Desmond has already said his report will include previously highly-classified documents relating to the murder.