State employees actively furthered and facilitated the loyalist murder of Belfast solicitor Pat Finucane but there was no over-arching conspiracy, a Government-commissioned report has found.
Sir Desmond de Silva's review of the 1989 murder of the Catholic father-of-three found collusion by the state went beyond a failure to prevent the crime.
Sir Desmond examined the role of two British agents in the murder and found another man involved was later also recruited as an agent, even though he was suspected in the UDA murder of Mr Finucane.
While the QC accused successive UK governments of a "wilful and abject failure" to implement an appropriate legal framework for running agents within paramilitary groups, he said no minister was aware of the plot to kill the solicitor.
Prime Minister David Cameron told the House of Commons the murder was "an appalling crime" and said the degree of collusion exposed was "unacceptable".
I a message to the family, Mr Cameron said: "I am deeply sorry."