A report into the loyalist murder of Belfast solicitor Pat Finucane will be published later today.
The Prime Minister ordered the review, which runs to 500 pages, following security force collusion in the lawyer’s death.
David Cameron is to make a statement to the House of Commons this afternoon.
Mr Finucane, 38, was shot at his north Belfast home by loyalist paramilitaries from the Ulster Defence Association in 1989.
The killing was one of the most controversial of the 30 years of violence in Northern Ireland because of allegations of security force collaboration with loyalists.
Mr Cameron has already accepted that collusion took place and apologised.
He ordered a review by Sir Desmond de Silva QC.
Mr Finucane’s widow Geraldine has vowed to keep up a campaign for a full public inquiry into the gun attack, regardless of the findings of the review.
Family members are expected in London today for publication of the report. They have been critical of the £1.5 million probe, saying it falls short of the full public inquiry they demanded.
Sir Desmond has already said his report will reveal previously highly-classified documents relating to the murder.
The loyalist paramilitaries shot Mr Finucane 14 times as he sat eating a Sunday meal at home, wounding his wife in the process. The couple’s three children witnessed the attack.
The former head of the Metropolitan Police in London, Sir John Stevens, has investigated collusion claims surrounding Mr Finucane’s death.
Shortly after starting the new inquiry, the Stevens team charged former Royal Ulster Constabulary Special Branch agent and loyalist quartermaster William Stobie in connection with the killing.
In November 2001 the case collapsed and he was shot dead outside his home within weeks.
In September 2004 a loyalist accused of murdering the solicitor pleaded guilty to murdering him. Ken Barrett entered his plea at the beginning of his trial.
In 2004, retired Canadian judge Mr Justice Peter Cory, asked by the Government to investigate cases of suspected collusion, concluded that military and police intelligence knew of the Finucane murder plot and failed to intervene. He recommended a public inquiry.
That year, Barrett was sentenced to 22 years’ imprisonment.
In 2004, then Northern Ireland Secretary Paul Murphy announced an inquiry under new legislation introduced in 2005.
The Finucane family opposed the Inquiries Act 2005, arguing it would allow government to interfere with the independence of a future inquiry because a government minister could rule whether the inquiry sat in public or private.
As a result, plans to establish an inquiry were halted by former Northern Ireland Secretary Peter Hain.
In October 2011, the Government ruled out a public inquiry into Mr Finucane’s murder but put forward a proposal for a leading QC to review the case. That review is to be published today.