Few could ever have imagined that Tony Blair's first year in power would be crowned by a political settlement in Northern Ireland. Few, indeed, would have imagined Northern Ireland would rate high priority at all during a first Labour term. As it is, according to the Prime Minister's official spokesman, the North has commanded more of Mr Blair's time than any other single issue.
The sensational result was laid before the people of Northern Ireland last night, a new political dispensation spanning the totality of relationships within these islands, rooted in the principles of consent, non-violence and inclusivity.
Incredibly, just a week ago Mr Blair held a series of crucial meetings with the Taoiseach on the margins of the Europe Asia conference. As he played host to heads of government, the British Prime Minister interspersed his meetings with Mr Ahern with endless telephone calls to David Trimble, John Hume, Gerry Adams and the other leading players in the multi-party talks process.
At issue were the high political and fine legal and constitutional details of yesterday's 67-page agreement covering everything from the government of Northern Ireland and the legislative basis for the new North-South council, through the remit and competence of cross-Border implementation bodies, to the vexed questions of equality, prisoner releases and policing reform.
According to one senior member of the Irish delegation - and this at a point of "great differences" between London and Dublin - Mr Blair's grasp of the detail was "absolutely amazing". The more amazing given a widespread perception that detail is not always Mr Blair's strongest suit, and that it should be deployed in an area of government offering little obvious reward to a party returning to power after 18 years in opposition.
But not so surprising, perhaps, to those who know Mr Blair well, like Mo Mowlam and, yes, David Trimble. Their relationship reportedly began with a visit to the Upper Bann constituency by Mr Blair while still leader of the Opposition. Mr Blair took tea at the home of a local farmer and his wife. They clearly got on well, and on the journey back Mr Blair remarked that they were nice people. Mr Trimble then told the Labour leader of the family's experience at the hands of terrorism.
Words of sympathy and outrage might have sprung readily enough to the lips of a seasoned politician. But by this point Mr Blair was engaged in a series of party manoeuvres which were to have a direct impact on his capacity to act on coming into power.
With the elevation of the Northern Ireland portfolio to shadow cabinet rank, he began to reposition Labour in the context of the developing peace process, and the Downing Street Declaration. Labour under his management would emphatically not be "a persuader" for Irish unity.
The depth of Mr Blair's own commitment to the principle of consent had been plainly revealed in an extensive interview with The Irish Times. And to the amazement of many, after just two weeks in Downing Street, on May 16th last year, Mr Blair made his first official trip and first major speech, in Belfast, on the future of Northern Ireland.
The press were slow to sense the quickening pace of Mr Blair's engagement with the Northern Ireland issue. Mo Mowlam was busy preparing her pitch for a second IRA ceasefire even as Labour conspired to keep the North out of the general election campaign.
In a series of interviews she signalled her readiness to meet the crucial Sinn Fein demands for a fixed point of entry into negotiations, together with a time-limited period for them. But while she and her officials edged their way back into formal contact with the republicans, it was the May 16th speech which set the crucial stage for the government's overall strategy.
Mr Blair told his audience he valued the Union; that they had nothing to fear from a Labour government; and that even the youngest in his audience was unlikely to live to see the North as other than part of the United Kingdom.
In the elation of Labour's stunning election victory, even sceptical Ulstermen appeared eager to share in the sense of change. It was not to last long. Dr Mowlam would swiftly lose her approval rating right across the unionist board. And a formidable coalition of unionist opinion is preparing now to try and derail last night's agreement.
But trust in Mr Blair's commitment to consent, and his determination to see the territorial claim withdrawn as the price of a new deal with the Republic, were the ingredients of the Blair-Trimble chemistry without which it would not have been possible.