The IRA have said sorry because they want to create an impression of humility

The disbanding of the IRA will happen in your lifetime and mine. It's the inevitable result of Sinn Fein's political success

I didn't believe I would ever see them do it. The statement of apology was one of the more surprising declarations of recent Irish history. The Provos are generally in the habit of blaming everybody else for the bloody consequences of their actions. "We might have planted the bomb, but it's the British presence that is ultimately to blame, etc." So when they come out and admit the blindingly obvious and say sorry, then, yes, we are entitled to be taken aback.

But surprise does not equate with unqualified approval. Not by a very long way. When the IRA said it was sorry for the pain caused to non-combatants, when it acknowledged "mistakes" and "failures", it was merely beginning a process. Nobody, least of all the Republican leadership, can believe that words of apology draw a line under the past. Not least when the IRA is still torturing and maiming people it has condemned as "anti social elements".

The more cynical interpretation of the IRA statement posits that it was intended to forestall criticism from the Northern Ireland Secretary in the House of Commons next week. (The Government has come round to accepting that the continuing terror of punishment attacks is hardly consistent with an organisation supposed to be on cease-fire. Of which more later.)

I think government pressure may have had something to do with it, but doing something as unprecedented as saying sorry is more likely to have been motivated by deeper historical forces.

For the first time in modern Irish history, Republicans truly sense themselves to be winning. The theology of glorious failure which sustained the movement for generations has been buried. As W B Yeats said of a different time: "Romantic Ireland's dead and gone/it's with O'Leary in the grave."

In today's context it's been consigned to the grave in favour of smart suits, slick publicity machines and an electoral machine that is the envy of every other party, north and south. With an unprecedented showing in the general election in the Republic and having overtaken the SDLP as the main nationalist party in the north, the Republicans are in a position to be generous. Gerry Adams and Martin McGuinness are masters of the "long-view" school of politics.

In the long term they believe a British government will quit Northern Ireland. The Downing Street declaration in which Britain forswore any "selfish" or "strategic" interest in the province was regarded by Republicans as the beginning of a long process of disengagement. The hardliners in the Unionist camp believe the same thing – nothing is more responsible for the ongoing sectarian bitterness in working-class Protestant areas than the loss of the sense of superiority over the Catholic minority and the pervasive fear of a looming united Ireland.

The loyalist paramilitaries may organise the violence, but there is no shortage of rage for them to exploit. The pragmatists led by David Trimble suspect it, but believe they can forestall such a day by participating in an internal settlement. Thus did the inconceivable come to pass: Unionists sitting at the same Cabinet table as Sinn Fein.

In the shorter term, the Republicans calculate that Sinn Fein might – in, say, 10 to 20 years – become the main party in the south and the unchallenged leader of Northern Ireland's nationalists. Is this a fanciful proposition?

The struggle in the south will be a lot harder than Sinn Fein realises and will require the party to drift far more to the middle ground. But Gerry Adams has no intention of spending the rest of his political life shouting from the sidelines. He is a very clever man and an arch-pragmatist. He is also tougher than anybody else involved in this process.

Thus the IRA apology is part of a longer-term strategy: create the impression of humility and put distance between the Republican movement of the present and the men who planned and carried out the slaughter. The timing may be useful in terms of Sinn Fein's current difficulties over punishment beatings, but the principle was decided long before now and it has everything to do with the political ambitions of Sinn Fein. The party's strategists know that the vote achieved in the Republic's general election would have been unthinkable during the IRA campaign.

The apology goes only so far, of course. The key players in the IRA's long war are still the key players now. Many of them are leading figures in Sinn Fein. They might collectively say sorry, but as for anybody individually accepting responsibility and bowing out of political life, forget it.

Yet there is an important lesson to be drawn from this apology. Political ambition has rendered the Republican movement immensely vulnerable to the pressure of public opinion. Sinn Fein has no intention of going back to the days of being the neighbourhood skunk.

This process will end with the disbanding of the Irish Republican Army. It will happen in your lifetime and mine. It is the inevitable consequence of Sinn Fein's political success. There are many in the IRA who haven't realised this is the case, but I am convinced it is coming. There are a number of immediate steps which need to be taken before that historic moment arrives.

Next week the Government is expected to outline its views on the continuing fascism practised by the IRA and loyalist paramilitaries against their own communities. Since the cease-fire the IRA has been torturing and shooting so-called "anti-social elements", ie joy riders, burglars, drug dealers and anybody who happens to cross the local IRA. This activity, much of it directed against children and adolescents, places Republicans in the same company as the torture squads of Latin America and should long ago have been recognised as a breach of the cease-fire.

These attacks are an instrument of control for the paramilitaries. Last year they ordered 700 people to leave their homes. There have been occasions when entire families have been forced to leave because of the misbehaviour of one member. In the first few months of this year the paramilitaries shot and battered around 60 people. And it goes on.

Just the other night in Antrim a man was abducted and shot in the arms and legs. The fact that they enjoy tacit acceptance on the part of many in the community doesn't mitigate the horror in the slightest, nor does it suggest that the paramilitaries are stepping in only because the police will not act. The police would deal with the crime if the IRA released its iron grip.

If Mr Reid publicly declares that any continuation of such brutality will be regarded as a breach of the cease-fire, he will be challenging the Sinn Fein leadership. But an organisation led by tough pragmatists must surely know that punishment attacks, and the kind of mischief-making we saw in Colombia must now come to an end. If not, Sinn Fein will deserve to suffer the political consequences, and the apology for the past 30 years of violence will be seen as the ultimate bad joke.

The writer is a BBC Special Correspondent