A loyalist paramilitary gang was involved in up to 15 murders in the 1990s while being protected by Special Branch handlers, a damning report said today.The report pointed to "disturbing" levels of collusion between the security forces and the paramilitaries.
The document was the result of a three-year inquiry by the Police Ombudsman, Nuala O'Loan. It found that in return for acting as informers, members of the Ulster Volunteer Force (UVF) had escaped prosecution.
She found that information on their crimes had been withheld from detectives investigating the killings.
The man at the centre of the scandal, identified in the 160-page report only as informant number one but known to be the former UVF man Mark Haddock, was paid at least £79,840 during the period under investigation, from 1991 to 2003.
The ombudsman concluded that her investigation had established collusion between certain officers within Special Branch and Haddock's UVF unit, based in the city's Mount Vernon district.
Her staff had unearthed intelligence within the policing system - most of it reliable and corroborated by other sources - linking the informants to the murders of 10 people, she said.
The gang was associated with 72 other crimes, including 10 attempted murders, 10 punishment shootings, 13 punishment attacks, a bombing in Monaghan, in the Irish republic, and 17 instances of drug dealing, as well as criminal damage, extortion and intimidation.
The Police Ombudsman's investigators also identified less significant and reliable intelligence linking the UVF men to five more murders.
The revelations are highly damaging for policing in Northern Ireland and for the reputation of the now replaced Royal Ulster Constabulary.
Mrs O'Loan said: "It would be easy to blame the junior officers' conduct in dealing with various informants, and indeed they are not blameless.
"However, they could not have operated as they did without the knowledge and support at the highest level of the RUC and the PSNI [Police Service of Northern Ireland]."
Mrs O'Loan's investigative team interviewed the Northern Ireland chief constable at the time, Sir Ronnie Flanagan. However, up to six officers at the level of assistant chief constable or detective chief superintendent in the Special Branch refused to cooperate. They either did not reply to requests for interviews or their lawyers sent letters on their behalf refusing to take part.
The investigative team did not speak to the loyalist informer at the centre of most of the allegations.
A source close to the £2m inquiry said: "If you've got intelligence that an informant you are handling has murdered and you do nothing, and it happens again and then again and then again, you've got a serial killer on your books who you are paying a salary to, immunising and protecting from prosecution.
"Collusion is the conclusion which emanates from that."
Tony Blair's official spokesman said: "This is a deeply disturbing report about events which were totally wrong and which should never have happened.
"The fact that they did is a matter for profound regret, and the prime minister shares that regret.
"But this is also a report about the past, and what is important now is that, under the new structures introduced along with the formation of the Police Service of Northern Ireland, these events could not happen now.
"What matters at this stage is that the whole community supports that process of transformation."
The then chief constable of the PSNI, Sir Hugh Orde, said the report made shocking reading, but systems were now in place to ensure the situation described would never happen again.
"The report ... doesn't reflect well on the individuals involved, particularly those responsible for their management and oversight," he said.
"While I appreciate that it cannot redress some of the tragic consequences visited upon the families of those touched by the incidents investigated in this report, I offer a wholehearted apology for anything done or left undone."
Sir Hugh said he accepted all the recommendations.
"Significant reorganisation and the new systems and processes to deal with this most difficult area of policing, which we have put in place over the last four and a half years, will ensure that the situation described by the ombudsman could never happen again in Northern Ireland.
The Northern Ireland secretary, Peter Hain, said the report had "shone a light into what was a very dark corner of behaviour by a limited number of Special Branch officers in the 1990s".
He said former UVF paramilitaries and police officers alike should stand trial for the crimes.
"There are all sorts of opportunities for prosecutions to follow. The fact that some retired police officers obstructed the investigation and refused to cooperate with the police ombudsman is very serious in itself," Mr Hain said.
Ms O'Loan's inquiry started with the 1997 killing by the UVF unit of a 22-year-old Protestant man, Raymond McCord, who had been a member of the group.
The victim's father - also called Raymond McCord - said Haddock, the UVF's commander at the time, was protected by police because he was on the Special Branch payroll and was providing information on UVF activities.
Mr McCord said he had turned to Ms O'Loan after senior police officers dismissed him as "some sort of crank".
The published report did not identify by name any of the retired Special Branch officers involved in collusion. A a secret version that does include the names, however, was delivered last Friday to Mr Orde, Mr Hain and a handful of other British officials.
Johnston Brown, one of the former detectives arrested and questioned by Ms O'Loan's investigators, alleged many rank-and-file detectives had been prevented from doing their jobs by a Special Branch elite that hoarded information.
Mr Brown, who was a detective in the police's criminal investigations division, said Special Branch colleagues had repeatedly blocked efforts to solve crimes involving members of the UVF and another outlawed loyalist group, the Ulster Defence Association.
In a statement, a group of former Special Branch officers rejected the reported findings. The former officers said they had always acted in the best pursuit of justice and had "nothing to be ashamed of".