Robin Cook got it exactly right when he said the objective is to avoid any death penalty and any lashes. Any British government, whatever its political complexion, however anxious it might be about trade or oil, could do no less than intercede to prevent brutal treatment of British citizens, guilty or innocent. But it need do no more than that, certainly not pander to the hysterical tone which has accompanied reporting of the accused British nurses in Saudi Arabia. We need to recognise this story is richly cross-cut by questions of cultural relativism, racism, Islam- phobia; it has also thrown up unsavoury evidence of prurience.

There are such things as universal human rights - that belief is a cornerstone of our civilisation - and they probably include protection against cruel and unusual punishment. But there are also such things as tolerance of local circumstance and recognition of the diversity of morals. There are also the obligations which travellers or residents in a foreign country take upon themselves. The intolerance of strict Islam for the consumption of alcohol, among other things, is well known. To go and live in Saudi Arabia as a matter of choice is also to accept, temporarily, the jurisdiction of Saudi police and Saudi judges.

The desert kingdom has been pretty much of a known quantity since at least Richard Burton's time, and anyone going there to live, including British nurses, has done so in the knowledge that Saudi ways are emphatically not our ways. Living abroad is to enter into an implicit contract with the host country: take its pay, observe its rules. When things go awry, the contract does not cease to be valid.

British justice is not impeccable nor - which may be more to the point in this case - is the conduct of investigating police officers. That said, the performance of Saudi institutions leaves some big questions pending, and they have nothing to do with sharia law or the principles of Islam. The Saudi government, evidently anxious to palliate opinion in Britain, despite the harsh language of its ambassador in London, has fallen between two stools, neither treating the case as it would have done if, say, Filipino maids had been involved, nor ensuring that the suspects were treated in Western fashion. The involvement of the victim's brother has further muddied the water.

None of that is to challenge either the legal competence of the Saudis to try the case according to precedent, nor their capacity to find and punish Nurse Gilford's killers. Saudi Arabia may be a nepotistic oligarchy where the proceeds of oil extraction have fed an orgy of materialism (and a series of deeply ambiguous interventions in Middle Eastern politics) but that does not permit the inference that no justice is possible in the kingdom.

The Saudis, moreover, will justly note the sudden change of tack on the part of British newspapers who not long ago were all too keen on the application of bamboo canes to bare backs - as long as the wielders were stout British turnkeys and the backs belonged to youthful malefactors. There is in short a whiff of racism in the air. The fact that elements in latter-day Islam are deeply misogynist is of no direct relevance, except that the accused nurses have alleged they were sexually abused by investigating police officers, a charge that would have been impossible to lodge if women in Saudi Arabia were given even elementary public recognition and civic protection.

Robin Cook needs to keep his nerve and stick to proper intercession with what is after all one of Britain's closest diplomatic partners in the region. His task would, it must be said, be easier had he not recently been buckling on the breastplate of international relations righteousness and proclaiming an ethical foreign policy in absolutist terms. To strive to conduct relations with foreign countries on the basis of a set of values is one thing; to announce in grandiloquent terms that henceforth Labour's foreign relations would be squeaky clean is another, and Mr Cook risks being held to account to impossible standards.

Perhaps this case will give him a chance to get a better grip on what he intends. The sale of arms to and diplomatic support for Saudi Arabia constitute a large British interest: that contention has not been challenged. As a general rule the internal affairs of the Arabian peninsula are not our concern, and we expect British nationals working there (for their personal benefit) to play by local rules. What that leaves as government's role in the case of Nurses McLauchlan and Parry is not great. To plead for clemency, to deplore treatment that British opinion regards as barbarous - these are the least and the sum of appropriate official intervention.