There can be few people who turned to their newspaper yesterday and were not shocked and appalled by the images of abuse and humiliation that confronted them. The unanimous verdict, by MPs, the Army and ordinary citizens is that, whatever the brutalities and dangers of war, such behaviour is unacceptable. It is also recognised that such degradation, both of the victims and of the abusers, has brought shame on Britain, on its Armed Forces and on the Royal Regiment of Fusiliers in particular.

But this behaviour is equally unacceptable to the vast majority of other soldiers and in no way reflects their attitudes. Overwhelmingly, the 65,000 troops who have served in Iraq over the past 22 months have done so, as the Prime Minister noted, “with distinction, with courage and with great honour to this country”.

Sadly, that point will not necessarily be the initial reaction of viewers in the Arab and Muslim worlds looking at the obscene photographs beamed around the Middle East. Damage has been done to Britain’s standing, and the smug superiority evident in some comments by Britons on the impact on America of the Abu Ghraib scandal is entirely misplaced.

In both countries, however, unlike in much of the Arab world, due process is now running its course. After anarchy comes the rule of law. The question that the British Army must now face is whether such a lapse was an aberration or whether there was a systemic failure in discipline and command. The three men now being court-martialled in Germany insist that they were “only following orders”, and that they had been encouraged by superiors to capture looters and “work them hard”.

Whatever the truth, serious questions must be raised about their immediate commanders. Why did allegations of abuse surface only after a fourth man involved, who has been convicted, take photographs to a high street shop to be developed? If their immediate superiors were not aware of any abuse, why not? And if they were, what action was taken to stop it? No one should be more concerned to hold a full inquiry than the Royal Regiment of Fusiliers, which already suffers from a rough-and-ready image within the Army.

The immediate outcry will probably be greater in Britain than in Iraq. Most Iraqis have more pressing daily concerns in the violent run-up to the elections, and they will be unmoved by glib and nonsensical comparisons to the effect that such behaviour is as bad as, or even worse than, that of Saddam Hussein. Within this country, however, the impact on national debate will, and should, be considerable. That said, it is important to retain a sense of proportion.

Many of the more sweeping comments are being made by those who have always opposed the Iraq war and who want to use these photographs to prove points unrelated to the abuse itself. There is no objection to their voicing opposition on political grounds. Nevertheless there should be considerable revulsion at any attempt to besmirch the Armed Forces in general and the soldiers serving in Iraq in particular on the basis of what has undoubtedly been exceptional and intolerable behaviour.

A full inquiry must await the end of the court-martial. There is little doubt that it must be rigorous, intrusive and cathartic.