The importance of the IRA giving up even just one Armalite cannot be overestimated

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Ulster security posts to be pulled down

IRA begins to lay down its arms

Moves on policing at the heart of historic decision

The IRA statement in full

The Commission statement

The reaction in Northern Ireland

'Rebuilding a community as divided as this is going to take a generation'

The importance of the IRA giving up even just one Armalite cannot be overestimated

What the IRA has in its armoury

Symbols of British 'occupation' will be demolished

Leading article: A seismic shift by the IRA deserves to be welcomed

David McKittrick: Why politics beat the paramilitaries

For once, as Tony Blair indicated, the overworked term historic hardly does justice to the momentousness of what has happened in Northern Ireland. For this is the very action that many who claimed to know the true minds of Provisional IRA said would never, ever, happen. The announcement that the IRA has after all decommissioned arms ranks with the Downing street Declaration, the 1994 IRA ceasefire – which ended with the Canary Wharf bombing – and the signing of the Belfast Agreement on Good Friday 1998 as one of the truly big moments of the Northern Ireland peace process. But it is even more than that. For it stands every chance, in removing the one huge obstacle which threatened time and again to abort the process, in laying at least the foundations for a truly permanent and stable polity in Northern Ireland.

No-one, of course should assume, despite the deeply justified sense of euphoria and relief in Belfast, London and Dublin, that the future is going to be easy. This is more than the matter of the renegade Real IRA organisation whose members have never accepted the democratic way. The fulminations from Ian Paisley's Democratic Unionist Party that this is another example of "smoke and mirrors" politics from the republicans, is a reminder, if one were needed, of just how difficult it is going to be. It won't be hard to point to potential shortcomings in the latest IRA move – and no doubt harder line Unionists will be swift in doing just that. It will be said with some justice that if the – admittedly substantial – dumps being sealed are those inspected by Cyril Ramaphosa and Martti Ahtisaari then they have already been compromised and that the republicans' military wing could well have access to ample arms if it needs them. Loyalist decommissioning is far from assured.

But that cannot detract from the huge symbolic as well as practical impact of General de Chastelain's annnouncement last night that he was satisfied that the IRA had verifiably put arms beyond use. For better or worse, decommissioning, or rather the IRA's refusal to decommission, has been the monkey on the back of the peace process for the last three years, and arguably for the decade since John Major first began to put his faith in a negotiated settlement. The importance of the IRA so decisively overcoming, their fierce, if primitively militaristic, impulse that the abandonment of a single Armalite would amount to surrender, cannot be overestimated.

Several factors over the past weeks have contributed to the Provisionals' decision to accept the terms, including substantive concessions on policing, demilitarisation, and "on the run" ex-terrorists by the British Government, laid out at the talks at Weston Park in July – a decision that in early September still seemed highly improbable. First, and no doubt, foremost was the realisation that politics worked for republicanism. Sinn Fein's formidable successes in the general election were a vindication of its once unthinkable decision to allow two ministers to sit with Unionists round a Cabinet table at Stormont. It's now apparent that the republicans looked at the removal of those political instititutions which they had helped to build and did not like what they saw.

Another, no doubt, is the leadership of the key architects of the agreement, Unionist as well as nationalist and republican. It is not to subtract from the leadership of Gerry Adams and Martin McGuinness in persuading, cajoling and no doubt threatening their own military base into accepting that democracy might serve republicanism better than military means, to salute David Trimble's toughness and courage, whatever detailed faults he has exhibited from time to time, in sticking with the process against what sometimes seemed to be insuperable opposition from withinn his own ranks. Having told Mr Adams that he had "jumped" by accepting devolution without decommissioning, and that it was now the republicans' home, he finally drove his message home that he was not going to do it again.

But finally, the impact of international pressure in a world turned upside down since the atrocities of 11 September should not be ignored. Even before the mass murders, it was clear that a change at the White House was going to make the relationship between the US administration and the Irish republicans a much less cosy one than it had been in the Clinton presidency. Paradoxically, the huge self-inflicted embarrassment of the discovery that an IRA delegation had visited the Farc guerillas in Colombia, may have hastened the change of heart. For it infuriated Washington, as Richard Haas, the US State Department man responsible for Northern Ireland policy revealed. "Messing with the Farc is about as bad as it gets," Mr Haas told a British official. This made armed republicanism an uncomfortable place to be in Washington, not just in government but among Irish-American legislators. That was compounded when the Americans felt the impact of terrorism.

For Mr Blair himself – and for Bertie Ahern, the Irish Taoiseach – it is of course a huge vindication. Not only because, for all the mistakes that may have been made along the way, the Prime Minister, thanks to his persistence and belief in the process, has seen it back on track just when the darkest hour seemed to have been reached. But it is also because of the example to the rest of the world afforded by the discovery that peace works in Northern Ireland. In the past few weeks, Mr Blair has said in relation to the Middle East that he has learned from Northern Ireland that when the process stalls, men of violence fill the vacuum. If there had been no decommissioning, that lesson would have looked forlorn. Because there has been, and for all the hard questioning that will inevitably now begin, that logic now looks almost irresistible. The signficance of what has happened yesterday is first and foremost in Northern Ireland. But it goes further than that. It offers the real chance of showing some of the most troubled corners of the world that politics works.