The search for weapons of mass destruction in Iraq has deflected attention from the continuing search for peace in Northern Ireland. As each day passes without a solution to the political impasse, the danger of a drift back to violence mounts.

The next breakthrough in the peace process needs to offer the prospect of a lasting solution, but this will only come with a dramatic change in how we confront the trauma experienced over Northern Ireland. On all sides we have to start telling each other some hard truths. Painful, even dangerous it may be, but avoiding this massive leap in conflict resolution would mean that even if we can get past the current impasse we would only be back here again in another few months.

This is the type of hard talk I engaged in when I spoke at a commemoration of the hunger striker Bobby Sands last week. Talking in terms republicans would understand, I told the harsh truth that the negotiations on the future of Northern Ireland would not be taking place if it had not been for the military action of the IRA. Let me be clear, I abhor the killing of innocent human beings. My argument was that republicans had the right to honour those who had brought about this process of negotiation which had led to peace. Having achieved this central objective now it was time to move on. The future for achieving the nationalists' goals is through the political process and in particular through the Northern Ireland assembly elections.

The leadership of Tony Blair has undoubtedly produced advances. But the tragedy at present is that the peace process is being jeopardised by the government's suspension of the political process - in the form of the Northern Ireland assembly elections. This leads to a dangerous vacuum. Therefore I see my task now as doing all I can to get the political show back on the road, to create the kinds of formulations through which the IRA, the loyalist paramilitaries and the British army can all depart the scene without a sense of abiding grievance. No side will move if movement is portrayed as humiliating surrender.

Among British people there has to be an acceptance that the violence of the past 35 years had a root cause. It wasn't some pathological trait of the Irish. Britain faced such violence in virtually every colony from which it was forced to withdraw, from the Mau Mau in Kenya to the nationalists in India. We have to face up to the fact that without the armed uprising in 1916 Britain would not have withdrawn from southern Ireland. And without the armed struggle of the IRA over the past 30 years, the Good Friday agreement would not have acknowledged the legitimacy of the aspirations of many Irish people for a united Ireland. And without that acknowledgment we would have no peace process.

Irish republicans have to face the fact that the use of violence has resulted in unforgivable atrocities. No cause is worth the loss of a child's life. No amount of political theory will justify what has been perpetrated on the victims of the bombing campaigns. An acknowledgment is also needed that loyalist paramilitaries were motivated by the same dedication to their cause as IRA volunteers and that many British troops demonstrated similar bravery in what was in reality a long and brutal war. Above all else, republicans need to accept that the time for violence has gone. Only the political process offers the real prospect of a united Ireland at peace with itself.

Unionists must now appreciate that the majority of British people are indifferent to whether Northern Ireland is part of the UK or of a united Ireland. There needs to be an honest admission that their position can no longer be sustained by a combination of paramilitary violence and the force of the British army. Given that within a generation there is likely to be a nationalist majority in Northern Ireland, Unionist politicians will serve their people best by preparing for that inevitability, rather than continuing to jockey for personal position.

Despite my 25 years' involvement in Northern Ireland politics, the tabloid-led response to my recent remarks took me by surprise. After all, I've been speaking at this annual event for more than a decade, and throughout the 1980s and 1990s I expounded the same message: that with political will on all sides, the period of armed struggle could be replaced by engagement in a peaceful process capable of realising the nationalists' historic goal, a united Ireland.

Why, I wonder, has my speech become an issue now - both for the media and for nameless spokespersons within the Labour party? We should put behind us the days when the tragedy of Northern Ireland is used by British politicians and media for short-term gain. Certainly the constructive expression of an alternative policy approach has never in the past been the basis for a threat of expulsion from the Labour party.

· John McDonnell is MP for Hayes and Harlington, chair of the socialist campaign group of Labour MPs, convener of the RMT and FBU parliamentary groups, chair of the Labour party Irish society and secretary of the all-party Irish in Britain parliamentary group.