Now even the Tories want to give peace a chance

The implications of the unconditional offer by Iraq to accept a UN weapons inspection alter the terms of political trade for all three of our parties as they prepare for the conference season and next Tuesday's Commons debate.

For Tony Blair, the new circumstances put him firmly on the defensive with most of his backbenchers. Already Labour MPs have shown themselves to be distinctly queasy at the prospect of a military conflict. There has been no appetite for the Prime Minister's close association with President Bush, but Mr Blair has re-gained the initiative during the past fortnight with his recall of Parliament and the prospective publication of the so-called dossier on the Iraqi threat.

The general view in the Government was that public opinion could be swayed if Britain and America were backed in any pre-emptive strike by a United Nations Security Council resolution. The latest opinion poll has shown an increase in support for military action – but this was published before the apparent Iraqi capitulation.

All these calculations should be revised, now that unhappy Labour MPs are saying that the weapons inspectors must be given a chance. They are now very much in the driving seat, and will be deeply angry if the Prime Minister simply repeats in the Commons yesterday's American line that the Iraqi response is "giving false hope to the international community". While the President and the Prime Minister may have limited faith in the UN, it is a body that is a deeply ingrained article of faith for most Labour MPs. Any suggestion that unilateral action should be contemplated outside its authority is regarded as inconceivable. But now that there appears to be a clear and unequivocal response from Iraq, the dissenters will be emboldened to stand up to Mr Blair.

So far, Mr Blair has always relished taking on his own supporters. We had a taste of this during his speech last week to the TUC. Until yesterday we might have expected more of the same in a fortnight's time at the Labour Party conference. Now he will have to make concessions, and in more than just rhetorical terms, to an overwhelmingly anti-war audience.

Labour MPs are unimpressed by Jack Straw's decision to treat the Iraqi offer "with a high degree of scepticism". They want to see clear signs that Mr Blair is his own man. In fairness, it could be argued that he has done more than anyone to influence Mr Bush on engaging with the UN. In the Cold War days, previous presidents would have seized on Kofi Annan's announcement – claiming it as a personal diplomatic triumph – with the British bathing in the reflected glory of their own influence.

The latest developments may also strengthen the doves in the Cabinet who, in the ascendant during the summer, appear recently to have been in retreat. The threat of resignation that appeared to surround Robin Cook and Clare Short had receded. But the doves could soon be flying around the cabinet table again when the Cabinet is convened, it is believed, on Monday. (Amazingly, it has not met since the end of July.)

The new situation also poses difficulties for the Opposition. I have been amazed at the growing number of Tory MPs who are just as unenthusiastic about military action as the Labour left, and who are far from happy at Iain Duncan Smith's uncritical attitude to Mr Blair's policy. In addition to the former shadow foreign secretary Francis Maude, the recent frontbench spokesman Peter Ainsworth (who stood down in the July reshuffle for family reasons) has also gone public with his reservations. They will both be emboldened by the latest UN developments, and have been joined by Steve Norris.

Although the Conservative Friends of Israel group has traditionally had a vocal impact on the front bench, the Arabist leanings of other Tories should not be overlooked. Last year, after 11 September, most Tory MPs went with the flow and stayed "shoulder to shoulder" with Mr Blair. That is less likely now. Backbenchers such as Douglas Hogg, a Foreign Office minister during the 1991 Gulf War, will not feel constrained this time.

Perhaps the biggest gainers from all this will be the Liberal Democrats who are, for the most part, the united party of pursuing all peaceful avenues to their logical conclusion. Charles Kennedy and his foreign affairs spokesman, Menzies Campbell, will be free to stress the opportunities for the weapons inspectors, and can now present their party as united for peace without appearing unpatriotic.

The odds have shortened that next week's Commons debate will be characterised much more by a mood of "give peace a chance". Both Mr Blair and Mr Duncan Smith might be in for a shock.

mrbrown@pimlico.freeserve.co.uk