Mr Cameron told legislators the collusion was totally unacceptable and reiterated his previous apology to Mr Finucane’s family, but said an inquiry would not shed more light on the scandal.
The 500-page review of the case by barrister Desmond de Silva heavily criticised the actions of State employees, who he said “fu-rthered and facilitated” the shooting of Mr Finucane, 38, by the UDA in 1989.
The collusion included spreading propaganda that Mr Finucane was sympathetic to the IRA; one or more police officers proposing him as a target to loyalists; and the mishandling of state agents in the UDA who were involved in the murder. However it found no evidence of over-arching conspiracy by the authorities to target Mr Finucane.
Mr Cameron said: “Collusion should never, ever happen. So on behalf of the government — and the whole country — let me say once again to the Finucane family, I am deeply sorry.”
However, the Finucanes branded the review a sham and repeated their demand for an independent inquiry.
Mr Finucane was shot in front of his wife Geraldine and their three children inside their north Belfast home in Feb 1989.
His widow last night said the review was a “sham, whitewash and confidence trick”. She accused it of suppressing the truth and attempting to throw all blame on dead individuals and disbanded organisations while exonerating ministers, serving officers and existing security agencies.
“The dirt has been swept under the carpet without any serious attempt to lift the lid on what really happened to Pat and so many others,” she said.
Mr de Silva said there was widespread leaking of sensitive intelligence to loyalists by the security forces at the time — a total of 270 separate leaks in Belfast between 1987 and 1989. He also accused the security forces of actively attempting to thwart the investigation of Mr Finucane’s murder.
Loyalist Ken Barrett was convicted of Mr Finucane’s murder in 2004.
Taoiseach Enda Kenny said: “The De Silva report, and [Mr] Cameron’s statement acknowledge the shocking extent of state collusion in the murder of Pat Finucane and the efforts to subvert and frustrate subsequent investigations into that murder.”