Sharia law should never become part of the British legal system, the Archbishop of Canterbury said yesterday.

Justin Welby said the Islamic rules are incompatible with Britain’s laws, which have developed over 500 years on the principles of a different culture.

He added that high levels of immigration from Muslim countries can ‘have an impact on the accepted pattern for choosing a partner, on assumed ages of maturity and sexual activity, and especially on issues of polygamy’.

Archbishop Welby’s comments follow the release earlier this month of a highly critical Home Office report that said all couples marrying in mosques should also have to go through a legally-binding civil marriage ceremony to shield wives from injustices under sharia.

Justin Welby (pictured) said the Islamic rules are incompatible with Britain’s laws, which have developed over 500 years on the principles of a different culture

They also reverse the position taken by his predecessor Lord Williams, who backed incorporating sharia into the British legal system. Archbishop Welby set out his reasons why sharia should not win official status in a book, Reimagining Britain.

He said yesterday in advance of publication that British law has ‘underlying values and assumptions’ that come from a clearly Christian tradition. ‘Sharia law is not just about punishments,’ he added. ‘It is something of immense sophistication, but it comes from a very different background of jurisprudence to the one from which British law has developed over the past 500 years’.

The Archbishop said in his book that the arrival of large numbers of Muslims in Britain – there are thought to be 3.3million here – has led many to challenge the values of the majority population. Among these are the right of people to choose their own husband or wife, and the need for monogamous relationships.

He added: ‘There has been and remains a demand for the introduction of those aspects of sharia law that affect family and inheritance...

There are thought to be around 85 sharia tribunals in the UK. They settle disputes including divorce and business arguments among those willing to accept their jurisdiction

‘The problem is reimagining Britain through values applied in action can only work where the narrative of the country is coherent and embracing.’ The Archbishop said: ‘Sharia, which has a powerful and ancient cultural narrative of its own, deeply embedded in a system of faith and understanding of God, and thus especially powerful in forming identity, cannot become part of another narrative.

‘Accepting it in part implies accepting its values around the nature of the human person, attitudes to outsiders, the revelation of God, and a basis for life in law, rather than grace, the formative word of Christian culture.’

Archbishop Welby said that the way people understand home and family are a vital basis of society.

‘They face enormous pressures and need one legal basis of oversight and one philosophical foundation of understanding. For these reasons, I am especially sympathetic towards those Islamic groups that do not seek the application of sharia law into the family and inheritance law of this country,’ the Archbishop said.

There are thought to be around 85 sharia tribunals in the UK. They settle disputes including divorce and business arguments among those willing to accept their jurisdiction. But there are concerns some of those who appear before them – especially women – lack full freedom of choice and may be subject to processes that would never be allowed in a court of law.

The Archbishop's comments reverse the position taken by his predecessor Lord Williams (pictured), who backed incorporating sharia into the British legal system

The Home Office sharia review, carried out by academic Mona Siddiqui, said some courts operate discriminatory rules.

Men can divorce simply by demanding one, it said. But women are often obliged to pay large sums, sometimes seen as the equivalent of repayment of a dowry. In one case, a woman was denied a divorce until she paid her husband £18,000.

The Siddiqui report recommended that all Islamic weddings should be backed by civil ceremonies so that Muslim brides have the full protection of civil law.

Lord Williams backed the idea of sharia as a full part of the British legal system in a BBC interview and lecture ten years ago.

He said people should be able to choose which jurisdiction they preferred, a choice that would mean Muslims could opt for courts that accept polygamy and outlaw the payment of interest in financial deals.