Mrs Finucane guards the flame

David Cameron has proved adept, in dealing with historical issues arising from the conflict in Northern Ireland, at employing the simple but effective tactic of declining to defend the indefensible. His handsome and forthright apology over the Bloody Sunday killings by British forces in 1972 earned him much kudos in Ireland.

He was speaking about the murder of Pat Finucane, a Catholic solicitor gunned down in 1989 by assassins who resented his effectiveness in representing republicans. The gunmen were members of the loyalist Ulster Defence Association (UDA), a collection of brutal backstreet gangs, but immediately after the murder rumours circulated that they had been directed by British security personnel. Those allegations, which many thought far-fetched at the time, have now been formally confirmed.

The report by Sir Desmond de Silva, the lawyer commissioned by Mr Cameron to go through the papers in the case, lays out in meticulous detail how senior army and police intelligence officers colluded in the killings of Finucane and other republican sympathisers. This included helping to identify, target and murder the lawyer, supplying a weapon and facilitating its later disappearance, and deliberately obstructing subsequent investigations. On three occasions Finucane was known to be on UDA death lists but police, with the approval of the army and MI5,Britain’s domestic intelligence service, gave him no warning. The very idea of killing him was probably suggested to a UDA member by a police officer, Sir Desmond concluded. There was a flow of security-force information to the UDA: perhaps 85% of its intelligence came from official sources.

It also seems that two British agents working in the ranks of the UDA were involved in Finucane’s actual murder. One, planted there by the army, had gathered information on him and carried out a reconnaissance of his home. The second, working for the police, held guns for the UDA, and handed to a “hit team” a weapon used in the attack on Finucane. His handlers knew someone was to be shot: the de Silva report concluded that police could have acted to prevent the murder.

A third loyalist, who drove the gunmen to the solicitor’s home, was not an agent at the time but later told police he had been involved. Detectives wished to pursue him for the murder but, in a move Mr Cameron described as “extraordinary”, a Special Branch superintendent intervened and instead ordered his recruitment as an agent. The investigation was effectively dropped.

One of the few notes of consolation for the government was the finding that there had been no “over-arching state conspiracy to murder Patrick Finucane”, and that ministers were genuinely in the dark about the murkier aspects of intelligence work in Belfast. The report did, however, accuse successive governments of “a wilful and abject failure” to provide guidelines on how agents should be handled within the law—a criticism that will resonate today in police forces in England whose undercover agents have got up to no good.

Much has changed in Northern Ireland since 1989. The army no longer patrols the streets ofBelfast, though a diminished UDA is still out there, rioting in recent weeks in a dispute over flags. The peace process, and the shared government it led to, are rightly seen as a towering success.

But bits of the unburied past from time to time come to light, and require response. Geraldine Finucane calls this report into her husband’s death a “whitewash”. Mr Cameron is resisting demands for a public inquiry into his death. Enough has already emerged to move Sir Menzies Campbell, a Liberal Democrat veteran, to declare to his fellow MPs that “in the more than 25 years for which I have been a Member of this House, I cannot remember a statement from the Dispatch Box that has filled me with more revulsion and horror.”