Leading article: A corner of a foreign field

There could have been no sadder news for a Remembrance Sunday than the announcement of more British fatalities in Iraq. Even if the final toll from the attack on the British patrol boat near Basra goes no higher than the four confirmed - three others remain seriously wounded - it constitutes one of the worst single attacks British servicemen have faced in the country.

The easy thing in such circumstances is to stress the sacrifice of the men involved, and in terms that highlight their personal courage, while casting no adverse reflection on the mission they served. The Defence Secretary, Des Browne, did just that, describing the "events today in Iraq" as a "stark reminder of the perils" British servicemen face in Iraq.

Indeed. No one doubts they face a constant risk, or that the latest casualties died for the highest motives, trying to bring a little order to a distracted and unstable country. Their grieving families can take pride in that at least.

The harsh reality is that they were victims of a policy that has gone horribly astray, but to which the Prime Minister still clings with all the obstinacy of a cult member who cannot accept his idol has feet of clay. The fact is that British forces in Basra have long outlived their initial welcome. They are now so widely seen as invaders, and as part of the problem rather than the solution, that it has become impossible for them to do much good to the community or, it appears, preserve themselves from harm.

Tony Blair cannot and will not accept that, hence the recent stream of claims from various ministers, echoing President Bush's mantra about staying the course.

But the official line looks more untenable by the day. It has become clear since the tectonic plates shifted abruptly in the United States last week that a profound change of Iraq policy is on the horizon, the nub of which is the rapid withdrawal of allied forces from the country.

But, as yesterday's events showed, extricating troops from Iraq is going to be far from easy. A confusing array of militias is already trying to inflict maximum damage on the "occupiers" as part of their local internal power struggles.

When the British first went to Basra it was thought that, as an overwhelmingly Shia area, it would be safe and secure - and a marked contrast to the bitterly hostile "Sunni triangle" that fell into the American zone.

Now, however, the collapse of all order in Iraq has fuelled a deadly intra-Shia struggle for dominance. The nearer that British troops get to their inevitable departure, the more intense that struggle is going to become. Their presence will not keep the factions apart but will, perversely, continue to act as a magnet for the militias. The tragedy is that yesterday's victims are unlikely to be the last.