Stop all the clocks. He is dead. Saddam Hussein had a rather good death, and dictators shouldn't have good deaths. He went to the gallows in dignity, holding the Koran, urging reconciliation, his head uncovered amid his captors' balaclavas.

The grotesque exercise turned a brutal tyrant into something like a martyr, a victim of a victor's justice. After what Human Rights Watch called a "trial by ambush", because of the conduct of the defence and the rush to judgment, the execution was overhasty too, as if his captors felt they had to dispatch him before 2006 was out. Was this intended as a kind of new year message from George W Bush? For Auld Lang Syne?

The execution of Saddam may have brought "closure" to the White House, but it left a bitter taste in the mouths of the rest of us. He was executed under the auspices of an Anglo-American occupation that has brought little but death and destruction to Iraq. Even members of the Iraq Study Group in the US Senate accept that the people of Iraq are probably worse off now than under Saddam.

So, who is going to hold the executioners to account?

Who will try Bush and Blair, the authors of an invasion which was almost certainly illegal under international law and which has led to the deaths of hundreds of thousands of Iraqi civilians? Shouldn't they be in the dock?

They ordered the invasion of Iraq on the dubious pretext of disarming weapons of mass destruction which weren't there. They deceived the international community and their own people in order to justify the invasion of a country which posed no military threat. That is perilously close to prima facie evidence of a war crime.

Imagine if Iraq had invaded, say, Kuwait on the grounds that it was pre-empting a military threat? Actually, that's not far off what happened in 1990, and we went to war to expel Saddam from Kuwait on the grounds that he had breached international law. Now we stand accused of a similar violation.

No, I'm not saying that Tony Blair should swing for his crimes. But there must be some kind of recognition that this war has been a catastrophic error and some attempt to make amends. To execute Saddam while accepting no responsibility or guilt for what we have done to Iraq is shameful, and history will condemn us for it.

And let's not maintain the fiction that the US had nothing to do with this judicial killing. If the occupying powers had wanted to, they could, of course, have prevented Saddam's hanging. But Bush decided that the US public would rather warm to this exercise in Old West justice. And perhaps they will.

But this has done nothing for the prestige of the occupying powers in the region. The death of Saddam has only given his Sunni countrymen another reason for prosecuting the war. Another turn in the cycle of violence.

And the stench of hypocrisy will linger for years in the West as we slowly come to terms with the enormity of what has been done to Iraq in our name.