Nearly 85 sharia courts in the UK are regularly giving 'illegal' advice on issues including marriage and divorce, a report claims.

Decisions concerning marriages not recognised under English law, polygamy, and disputes regarding children are being made by the sharia courts, according to the report by the thinktank Civitas.

There is no clear divide between the functions of imams and the sharia courts. An imam who conducts a marriage which is not registered and then advises on disputes within that marriage acts in breach of the law and outside the scope of the sharia court's role, Civitas say.

Muslim arbitration tribunal (MTA), a network of sharia courts, has been operating in London, Manchester, Bradford, Birmingham and Nuneaton since 2007 under the 1996 Arbitration Act. These make decisions that are legally binding and can be enforced by the English courts, provided they do not conflict with English law and both parties choose to use them. But the report found that there are at least 85 shariah courts in operation.

Report author Denis MacEoin has called for Sharia courts not to be recognised under Britain's 1996 Arbitration Act.

The author of Sharia Law or 'One Law For All'?, said: "Sharia courts operating in Britain may be handing down rulings that are inappropriate to this country because they are linked to elements in Islamic law that are seriously out of step with trends in western legislation that derive from the values of the enlightenment and are inherent in modern codes of human rights.

"Sharia rulings contain great potential for controversy and may involve acts contrary to UK legal norms and human rights legislation"

He added: "The fact that so many sharia rulings in Britain relate to cases concerning divorce and custody of children is of particular concern, as women are not equal in sharia law, and sharia contains no specific commitment to the best interests of the child that is fundamental to family law in the UK."

The report's findings raise questions about the appropriate scope of tribunals under the Arbitration Act, experts say, which were not intended to deal with issues like divorce.

Sharia courts also need to be more transparent if they are to continue, critics say.

"These tribunals don't seem to have any system of record keeping" said MacEion. "They are not transparent – either within their own community or for the outside community. That is a problem that needs to be looked at."

MacEoin concluded: "The introduction of sharia law into this country is a recipe for a dichotomous legal system that holds Muslims and non-Muslims to different standards.

"This is not a matter of eating halal meat or seeking God’s blessing on one’s marriage.

"It is a challenge to what we believe to be the rights and freedoms of the individual, to our concept of a legal system based on what parliament enacts, and to the right of all of us to live in a society as free as possible from ethnic-religious division or communal claims to superiority and a special status that puts them in some respects above the law to which we are all bound."