UTV has strongly defended its controversial Insight programme on the murder of the leading human rights solicitor, Mr Pat Finucane.
The programme on Tuesday alleged that a taped confession to the 1989 killing disappeared within a week in 1991 and was replaced by a tape which did not include the confession.
Mr Finucane's widow, Geraldine, has repeated her demand for an independent public inquiry. Mr Finucane was shot dead by the UDA, but there have been persistent allegations of security force collusion.
"Tony Blair could call an inquiry if he wanted to. I don't know why that hasn't happened," Ms Finucane said yesterday. The killing is being investigated by the Metropolitan Police Commissioner, Sir John Stevens, but allegations his inquiry's remit. A former RUC Special Branch informer, Mr William Stobie, has been charged in connection with the murder, but the case is expected to collapse.
The programme claimed Special Branch figures obstructed vital evidence in the murder inquiry. Det Sgt Johnston Brown, who took early retirement last month, told UTV the identity of Mr Finucane's loyalist killer, who "boasted and gloated" about the murder, had been known since 1991.
The taped confession by the man, who was an RUC informer, allegedly disappeared. The programme claimed a decision was taken at a senior level of Special Branch to obstruct the murder inquiry.
Det Sgt Brown said he had been threatened at the time because of his stance. He claimed he was told he would end up in jail, or a gun would be planted on his son. The programme also quoted unnamed RUC sources who claimed the Special Branch allowed drug-dealers to operate with impunity in return for passing on intelligence.
An RUC source claimed Special Branch had kept files on other RUC officers, and those who questioned its activities were warned of "dire consequences". One retired chief superintendent said: "I fear Special Branch more than the Provisional IRA or the `Real IRA'. If I die in a road accident, I have told my wife to ensure there is a full investigation." UTV's head of news and current affairs, Mr Rob Morrison, said he had complete confidence in the veracity of the allegations made by RUC officers in the programme, which he said was the result of five months of intensive, investigative journalism.
He defended the decision to use unnamed sources for many of the allegations since the officers felt they could be targeted if they were identified.
An RUC spokesman declined to comment directly on the programme. "All the matters that the programme raised have been the subject of an intensive investigation by Deputy Assistant Commissioner Hugh Orde of the Stevens inquiry team and, because of this ongoing investigation, it would be inappropriate to make further comment," he said.
A Sinn Fein Assembly member, Mr Gerry Kelly, called for Special Branch to be disbanded.
An SDLP Assembly member, Mr Alex Attwood, said many serious and damaging questions about the activities of the security forces and services had been raised by the programme, and the British government should face up to the situation.