By Christopher Landau
The Archbishop of Canterbury's desire to bring some aspects of Sharia law into the mainstream legal system is bound to prove controversial.
But his view is that if Britain is to develop cohesive communities, the role that religion plays in the lives of some citizens must be taken seriously.
He argues that Muslims find themselves "faced with the stark alternatives of cultural loyalty or state loyalty" and that Britain will only be able to come to terms with its multi-faith society if its legal system learns to adapt.
The archbishop says that anxieties "haunt the discussion of the place of Muslims in British society", and that sensational reporting of opinion polls means that any debate around Sharia has become distorted.
He refers to the Muslim scholar Tariq Ramadan, who has written that "many Muslim intellectuals do not even dare to refer to the concept for fear of frightening people or arousing suspicion of all their work".
The archbishop accepts that Sharia is often the justification for appalling legal practices and punishments - but that is not what he is calling for.
"Nobody in their right mind would want to see in this country the kind of inhumanity that's sometimes been associated with the practice of the law in some Islamic states," Dr Williams says.
He concedes that his views put him at odds with the European Court of Human Rights, which regards Sharia as incompatible with democracy.
The archbishop regards the court's view as a "pretty sweeping judgement" that fails to account for the fact that there is no fixed code of Sharia law but different interpretations in different countries.
Dr Williams is keen that secular states think seriously about the impact that religion has on the lives of citizens, and as such that the legal system should be adapted to accommodate such beliefs.
He cites the example of medical professionals being able to opt out of performing abortions as an example "which is difficult to see why the principle cannot be extended in other areas".
The archbishop is clear that care is needed to distinguish "purely cultural habits from seriously-rooted matters of faith and discipline" when legal disputes occur - but that a system which takes Sharia seriously could be able to achieve that aim.
So why is a Christian archbishop advocating the place of Islamic law?
Because he fears the other option is a "standoff" where members of minority religious communities feel that the gap between their principles and the legal system of the state is so vast, the only option open to them is to opt out of the mainstream legal system.
That, in the archbishop's view, is a recipe for even greater levels of community fragmentation.