These killings will inflame public anger - and increase the pressure on Blair

The ambush of three Black Watch soldiers and their interpreter could not come as worse news or with worse timing for the British Minister. The move of British troops to support the impending US assault on Fallujah was never popular with his party, nor in the country. It smelt too much of a gift to the US President just as he faced re-election.

Nevertheless Tony Blair went ahead, not simply ignoring the protests from his own backbenchers but - just as he has done with the original decision to join the invasion of Iraq in the first place - spreading it around that the British forces possibly relished the move as a means of showing the US how much better we did things in the British sector.

Having led with our chin, we have had our nose bloodied. In military terms it is not a disaster. The Black Watch can learn and recover. That is their job. But in political terms, coming just as a triumphant President Bush has been re-elected, it could not be worse.There is now not the slightest chance that Mr Blair will be able to cast off the damaging idea that he is Mr Bush's poodle. He is saddled with his association with Mr Bush until and beyond the next general election. Having agreed to join in the US campaign on Fallujah, we are inextricably linked to the manner in which it is conducted, and the casualties both on our side and among Iraqi civilians. Each new disaster will remind the public how costly it has become to our alliances and our reputation. Having avoided joint public appearances with Mr Bush for months, he must now appear with him on the international stage. And every time, the British public will be reminded that the Prime Minister chose the alliance with Washington in the teeth of fierce public opposition and followed Mr Bush into a misguided and costly war.

Mr Bush's now unrestrained devotion to conservative values compounds the difficulties Mr Blair faces with his backbenchers and the Labour Party grassroots because of the war. The less apologetically Mr Bush leans to the right, the more uncomfortable Mr Blair's alliance will be, for him and for his party. The Bush wing of the Republican Party is about as far from the political mainstream in Britain as it is possible to be on such issues as abortion, gay rights and the role of religion in public life. The association with Mr Bush is an electoral liability Mr Blair could well have done without.

Nor is there any sign as yet that Mr Bush is prepared to reward Mr Blair for his loyalty over Iraq. In his statement congratulating Mr Bush on his re-election, Mr Blair described the Middle East as the most "pressing challenge" of today. There has been speculation that Mr Bush will chair a new conference in London in an effort to relaunch the peace process. Mr Arafat's likely departure from the scene may remove one obstacle to progress, while creating another - uncertainty about who leads the Palestinians. Yesterday, though, even as Mr Arafat's death was erroneously announced, Mr Bush spoke of the Middle East as but one of his foreign policy priorities. This does not bode well for any serious US engagement.

Mr Bush's re-election will also place Mr Blair once again on the spot over Europe. Under a Kerry administration there was at least the prospect of US overtures towards the European opponents of the Iraq war. The need for Europe and the US to "build anew" their alliance featured almost as prominently in Mr Blair's post-election statement as the Middle East. If there are to be overtures now, however, the likelihood is that they will have to come from the Europeans - and there is no guarantee whatsoever that they will. Indeed, far from fostering a renewal of transatlantic ties, the prospect of another four years of George Bush could well convince France, Germany and Spain, at least, that Europe should dare to consider a future beyond the Atlantic alliance. Once again, there would be no third way: Mr Blair would have to choose. His hopes of strengthening Britain's role as the bridge between America and Europe would lie in tatters, like those of so many British prime ministers before him.