The women had no doubt. Educated, young, articulate, they had one aim: to turn their country into a real Islamic state, run according to their interpretation of Islamic law, the shariat. Only then, they said, would they be protected from the chaos and violence of the modern world. Only then would there be an end to corruption and misgovernment. Only then would the country assume its true place as a Muslim nation.

The women were speaking in Rawalpindi, the crowded northern Pakistani city. All members of an Islamist party, they believed that the current system in Pakistan, where a secular legal system co-exists uncomfortably with a religious one, was doomed to failure. The coming of shariat was, they told me, inevitable.

They, like the archbishop of Canterbury, were interested in the degree to which the specific practices of a religious community, whether majority or minority, be allowed within the legal system of a nation.

All over the world, the same question is being posed. In recent years, with the weakening of the nation state and growth in alternative identities, often religious, it has taken on a new urgency, particularly in Western countries with large, newly assertive Muslim minority populations. The resulting tensions are becoming more and more obvious.

So in France, a country where the only identity officially recognised is that of 'citizen of the republic', last week's row provoked keen interest. The British system of multiculturalism is seen by many Frenchmen as evidence of an unforgiveable and incomprehensible laxness. Yet, at the same time that he demands 'immigrants' adhere to French values, President Nicolas Sarkozy has enraged defenders of his nation's aggressive secularism by insisting repeatedly that Europe has 'Christian roots' and that religion, in its broadest sense, is at the root of civilisation. In Germany and Holland similar debates are taking place as large immigrant communities, particularly those established for several decades, challenge the status quo, asking what their place is in 'Christian' countries?

In so doing, they bring to the West an element of a fiery debate that has been longstanding in the Islamic world. In Pakistan, for example, the argument over whether the state is 'a Muslim state or a state for Muslims' has never ceased, contributing greatly to its instability. Elsewhere accommodations have been found, often based on original settlements by colonial powers. So in India, which does not have a state religion, 140 million Muslims, like other communities, have retained their own civil laws governing marriages, divorces, deaths, births and inheritance. In overwhelmingly Muslim majority Egypt, religious minorities are governed under separate personal status laws and courts. The Coptic Christian minority in the country marry under Christian law and foreigners marry under the laws of their countries of origin.

And where Sharia law is applied, it varies too. In Saudi Arabia, there are frequent executions and amputations, justified by selective reading of the Islamic holy texts. Elsewhere such punishments are rarely or never applied. In Saudi Arabia too, women may not drive. In Bangladesh and Pakistan, they can. As there is no reference to motor vehicles in the Koran, the decision as to who can or can't drive them has been made by (male) Islamic scholars. States in the Islamic world have made repeated efforts over centuries to co-opt and control the clergy, frequently with disastrous results.

What is clear is that where there is sufficient demand for Islamic law, courts of some kind are likely to be found. In Afghanistan in the 1990s, in the anarchy of civil war, many initially supported the Taliban simply because they brought a form of order. In parts of western Pakistan, Islamic judges have long dealt out summary justice according to religious law and tribal customs. For locals, the choice between slow, corrupt and expensive state legal systems and the religious alternative, rough and ready though it may be, is not hard. Elsewhere, particularly in Africa, local religious holy men settle disputes.

There are also reports of 'informal' shariat courts in the UK. Although their rulings are not recognised by English law, participants often agree to abide by their decisions in the same way that Jewish civil disputes are often settled in their own, officially recognised court, the Beth Din. This is not surprising. That some measure of Islamic law is 'unavoidable' has already been recognised in the UK. British food regulations allow meat to be slaughtered according to Islamic practices and, as Islam forbids interest on the basis that it is money unjustly earned, the Treasury has approved Sharia-compliant mortgages and investments.

The women in Rawalpindi had no doubt why they wanted more rigorous application of Islamic law. Though educated, relatively wealthy and from solid family backgrounds, they said they felt disorientated and stressed by the pace and uncertainty of modern life. 'I know that in the law I have answers and that makes me calm,' one said.