Bad wars, in the modern age at least, end slowly amid exhaustion. They drag on through investigations and reports and speeches whose function is an endless search for justification. In the end there remains a simple question: was it worth it? Approaching the latest dreary benchmark in the war in Iraq — the presentation of the report prepared by General David Petraeus and US ambassador Ryan Crocker and the White House and Congress, it is a question that is gaining a powerful urgency on both sides of the Atlantic.

On Sept 1, it was the turn of General Mike Jackson, former commander of British forces, to say what many have said before and paint the US conduct after the invasion of Iraq as a miserable catastrophe driven by hubris and stupidity. His intervention joins an increasingly fractious debate between London and Washington, played out between proxies, in the shape of former generals such as Jackson on the British side and Jack Keane, an adviser to Petraeus, on the other, who has attacked as feeble the performance of British troops in Basra and the south, as troops are gradually withdrawn.

And while the political leaderships on both sides have scrambled to paper over the cracks and deny that there is a split, it is a disingenuous attempt. Recently retired generals speaking to dramatise the concerns of the present command are a deeply established military tradition. So we must assume that a very real split exists.

So, in British terms, was any of it really worth it? Certainly not for the several hundred thousand Iraqis who have lost their lives, now almost certainly outstripping the victims of Saddam Hussein in total. I look at the emails that I’ve received in recent weeks from officials and friends who worked enthusiastically in trying to rebuild civic society in the south and more widely throughout Iraq. The same words recur. ‘Unbearable.’ ‘A terrible loss.’ ‘Disaster.’ Recent conversations with British soldiers in Iraq who I encountered travelling through Baghdad voice the same emotions, speaking of a failure and overwhelming pessimism for Iraq’s future.

In the end, what have four years of British occupation of the south achieved?There is an absolute deficit of political accountability, still no effective system of policing or jurisprudence: in short, many of the attributes of a failed state. It is a moment of enormous nemesis in many respects following the hubris that has gone before. After the months and years in which the British officers boasted about their ‘soft-hatted’ approach, and the success down in the south, while criticising — explicitly and implicitly — their US partners in the north. They have come to the same thing.

A rash of recent reports to Congress , of which the Petraeus/Crocker report is the latest, has shown at last some honesty over what is really happening in Iraq, acknowledging the benchmarks that have been missed, most crucially the utter failure of the Iraqi police force. Perhaps it is an appropriate time for a similar candour in London. — The Guardian