Leading article: A timely reversal in Iraq

The terms of trade in the debate over Iraq have shifted decisively. Only a few months ago, anyone who called for British troops to be pulled out was dismissed by the Prime Minister as, in effect, an appeaser who was assisting al-Qa'ida in its propaganda work. Last month, The Independent on Sunday called for troops to be redeployed from Iraq to Afghanistan, with some withdrawal from Iraq possible early next year, reducing over 12 months to a token presence. We half expected to be condemned by ministers for undermining the morale of our troops, flouting the wishes of the democratic government of Iraq and inciting the insurgents to redouble their efforts. What we did not expect was that Margaret Beckett would agree with us.

Last Wednesday, the Foreign Secretary performed a most graceful manoeuvre in the House of Commons. So graceful that it was less of a U-turn and more of a parabola, a wide, sweeping arc. "There is no question of us cutting and running from Iraq," she began. A few sentences later: "That does not mean that things are standing still. Our approach has evolved significantly in recent months." So gradual was this evolution that few MPs realised the importance of her mention of transferring provinces to Iraqi control. "The progress of our current operation in Basra gives us confidence that we may be able to achieve transition in that province, too, at some point next spring."

We welcome this development of British foreign policy. Although this newspaper opposed the invasion of Iraq, we have the utmost respect for the British armed forces doing a difficult job in a dangerous situation. But it did them no good to insist that they must "see through" a mission impossible. What has changed? General Sir Richard Dannatt's defiance of Tony Blair last month was the significant moment. When the chief of the British Army says publicly that the presence of British forces "exacerbates" the security situation in southern Iraq, it becomes impossible to pretend otherwise.

The reality has not changed much since we "kicked the door in" in Iraq in 2003, to quote Sir Richard. The Western occupation was bound to be resented and to be a focus for nationalist violence. That was one of many reasons why this newspaper opposed the invasion. Yet, for most of the time since, we have not advocated British withdrawal because the consequences for the Iraqis in the south appeared to be worse if our troops left than if they stayed. That remains true of the US zone, including Baghdad. But Sir Richard's intervention confirmed that, in the British area around Basra, the calculation of least bad outcomes had shifted in favour of an early withdrawal.

We welcome Mrs Beckett's clarification of part of that timetable. But we wonder whether this might afford an opportunity to take stock of Britain's defence posture generally. We remain sceptical about whether British commanders have the resources they need to fight a necessary and winnable war in Afghanistan. Meanwhile, the debate about the future of Britain's semi-independent nuclear deterrent seems increasingly likely to take place after the Cabinet has reached its decision. What is needed is more of the kind of openness that Mrs Beckett demonstrated last week. When Des Browne, the Secretary of State for Defence, makes a speech to defence experts tomorrow, he has the chance to widen the public discussion of Britain's defence posture in general and our policy towards Iraq in particular. We encourage him to take it.