The US and Britain must now prepare an orderly end to their occupation of Iraq

It is hard to pin down exactly when the self-appointed liberators turned into aggressors in the eyes of Iraqis. Was it at the very outset, when US and British forces bombarded and then invaded their country without the cover of a UN resolution? Was it when US Marines laid siege to Fallujah, or when they sent tanks across the cemetery in the holy city of Najaf on a Friday? Or is it the cumulative effect of months in which US forces, but also the British, have increasingly treated Iraqis as second-class citizens in their own country, whether by ill-treating those they have detained or - as we report today - by their shameful failure to record the thousands of civilian dead?

It is hard to pin down exactly when the self-appointed liberators turned into aggressors in the eyes of Iraqis. Was it at the very outset, when US and British forces bombarded and then invaded their country without the cover of a UN resolution? Was it when US Marines laid siege to Fallujah, or when they sent tanks across the cemetery in the holy city of Najaf on a Friday? Or is it the cumulative effect of months in which US forces, but also the British, have increasingly treated Iraqis as second-class citizens in their own country, whether by ill-treating those they have detained or - as we report today - by their shameful failure to record the thousands of civilian dead?

Opinions may differ about when the line was crossed. Some US officials insist that their forces are liberators still, threatened by foreign fighters, Islamic fundamentalists and remnants of Saddam's regime. But it is surely time for the US and Britain to face the fact that in the eyes of very many Iraqis our forces are unwelcome, oppressive intruders. Far from fostering security and stability, they are a block to peace and a focus for attack. If Washington will not draw this obvious conclusion and prepare for an orderly exit, then our government must revisit its unconditional support for George Bush and weigh the consequences of retreating alone.

The first flickers of thinking about an exit strategy may underlie the hints flying around in recent days that the forces of occupation might be prepared to leave soon after the planned transfer of sovereignty on 30 June. First the US Secretary of State, then the Foreign Secretary, mooted the allies' readiness to pull their troops out of Iraq if asked to do so by a new Iraqi government. Yesterday, the Defence Secretary, Geoff Hoon, said that British troops would not stay in Iraq "one day longer than is necessary", while insisting that "for the moment it is necessary."

President Bush has since reverted to the language of completing the job that featured in most earlier US and British statements about Iraq. And the hints about an early withdrawal may have been more about convincing Iraqis that the return of sovereignty will mean something than about any other option that may be under consideration. On the British side, the mention of an eventual end to the occupation may also be a way of making more palatable the expected announcement that more - perhaps a lot more - British troops will be on their way to Iraq soon.

If more troops are to be sent at the request of British commanders to assist the British troops already there, that may be a necessary evil, and it is one that the Prime Minister and Defence Secretary should justify to Parliament. But there should be no question of the British taking responsibility for more territory because the US cannot cope. The whole emphasis now must be on preparations for getting out rather than getting deeper in.

Until one month ago, it appeared that the handover of sovereignty to Iraq would be accompanied by the return of the United Nations as guarantor and the arrival of new troops, including from European and Muslim countries, to form a genuinely multinational security force. This looks less and less realistic. More countries are withdrawing troops, or thinking of doing so, than are committing them. Yet for US and British to remain in Iraq, in their current formation under their current command, after 30 June, would expose the emptiness of our assurances about sovereignty.

Unless Iraq's interim government - the composition of which is still not determined - has a say in whether the troops stay and where and how they are deployed, sovereignty will mean nothing. Resentful Iraqis will only grow more desperate; security will deteriorate further, and there will be no possibility of the elections scheduled for January. In so far as there is a preferred timetable for a US and British withdrawal, it seems to be after these elections. If a messy, Saigon-style, withdrawal is to be avoided, our political leaders need to be planning for, rather than merely hinting at, an exit from Iraq much sooner than this.