The admission by Det Supt Kevin Geddes, the PSNI officer in charge of the Kevin McGuigan murder inquiry, that the Provisional IRA still exists, has access to high-powered weapons (one of the gunmen who killed McGuigan was armed with a semi-automatic rifle) and is so well organised that it has a command structure, has shocked the Irish political system, surprised many in the media and raised serious question marks over the survival of the powersharing government in Belfast.

But the revelation will have come as no surprise to two leading actors in the peace process drama at the time, in the summer of 2005, when the IRA announced the end of its armed campaign against the British presence in Northern Ireland, the point at which many people assume the IRA ceased to exist.

One was the then minister for justice in Dublin, Michael McDowell, and the other was George Bush's ambassador to the peace process, Mitchell Reiss.

They were involved in an extraordinary spat with the British prime minister, Tony Blair, and his Northern Ireland adviser and chief of staff, Jonathan Powell, over precisely this issue, namely the retention by the Provisional IRA of an armed capacity and, presumably, an organisation to wield it.

Reiss recalled the altercation in a stinging review of Powell's peace process memoir, Great Hatred, Little Room: "In July 2005, the IRA had finally agreed to decommission all its weapons. At the last minute, [Gerry] Adams called No 10 to demand that some of the weapons not be destroyed so that the IRA could arm itself against possible attacks from dissident members. Unless this was allowed, he threatened, decommissioning would not proceed. The Blair government conceded, but wanted to check with Dublin. Irish Minister for Justice Michael McDowell refused to acquiesce in the backsliding, despite enormous pressure. Powell told Adams of the problem, and Adams gave way. Decommissioning took place as planned."

So we know that the Sinn Féin leadership wished to retain the ability to inflict and threaten violence and we know also that at least some in the British political establishment were amenable. We do not know for certain, but must assume that Blair and Powell consulted the security service, MI5 before agreeing to Adams’s demand and that they secured acquiescence at least from that quarter.

So important elements in the British system were favourably disposed to the view that the Provisionals needed to defend themselves against possible aggression from political opponents and, if there was a matter-of-fact quality to Det Supt Geddes’s acknowledgment that the IRA had not gone away, it can only sustain the suspicion that this has been an open secret in the security world for a long time, that notwithstanding the qualms of Dublin and Washington, new weapons were acquired from elsewhere and a blind eye subsequently turned to the whole business.

Circumstances

Indeed the circumstances of the Kevin McGuigan killing were a textbook example of the sort of fears expressed by Adams to Tony Blair a decade ago. In May, a leading Provisional activist, Gerard “Jock” Davison, was gunned down near Belfast city centre. Very quickly a former comrade with whom he had quarrelled was blamed and a week or so ago he was killed. To what extent were the killers, and those who ordered them, motivated by the fear that failure to retaliate would be seen as weakness and could invite further attacks against even more high-profile targets?

The need to defend its leaders and members is not the only reason an armed IRA survives. The IRA is enormously wealthy and continues to raise money in unorthodox and dubious ways. Some years ago, admittedly before the 2008 crash, its property portfolio alone – homes and businesses in Ireland, Europe, the US and even the Caribbean – was estimated by the Garda Special Branch to be worth over €200 million.

Someone needs to own, protect and administer all that wealth. Someone needs to provide protection to those who raise money in other ways. Money creates the need. What follows are guns and organisation. But there can be little doubt that fear of bloody feuding, a seemingly inevitable consequence of republican political shifts in the past, was the main factor in the Provisionals’ decision to retain an armed wing. The remarkable aspect of the last 20 years or so of the peace process is that despite a deep personal and ideological split with the Real IRA in 1997 and numerous splinters since, there has been so little internecine bloodshed.

Carnage

Compare that to the carnage that followed the Official IRA-Provisional IRA, or Official IRA-INLA splits and the peace process can be seen as an astonishingly calm affair. The Provisional-Real IRA split was, by comparison, almost a civilised transaction, negotiated in a businesslike way with no side taking too hard a line for fear of the consequences. Would it have been different had the Provisionals disarmed and disbanded? Most probably.

To be fair to the Provisional IRA, the organisation itself has never said that it has disbanded and the most that Sinn Féin figures will concede is that, as Gerry Kelly put it on Thursday, "The IRA has left the stage." The stage perhaps, but not the theatre. The assumption that the IRA went away when it made its July 2005 announcement ending the armed campaign against the British is due almost entirely to an over-reading of the statement mixed with a large dollop of wishful thinking.

Nowhere in that statement did “P O’Neill” say that the IRA was disbanding. The precise words were: “All IRA units have been ordered to dump arms. All Volunteers have been instructed to assist the development of purely political and democratic programmes through exclusively peaceful means. Volunteers must not engage in any other activities whatsoever.”

In a crucial sense this was no different from the statement which heralded the end of the 1956-62 campaign: the IRA is stopping its war, will begin doing other things but is not going away. Subsequent new year and Easter statements refer variously to “the commitment and discipline of IRA Volunteers”. The IRA did not go away, not entirely. But for a lot of people it was comforting to believe that it had.

Ed Moloney is author of A Secret History of the IRA