The House of Lords today drew stark attention to the conflict between sharia and UK law, calling the Islamic legal code "wholly incompatible" with human rights legislation.

The remarks came as the Lords considered the case of a woman who, if she was sent back to Lebanon, would be obliged under sharia law to hand over custody of her 12-year-old son to a man who beat her, threw her off a balcony and, on one occasion, attempted to strangle her.

The woman was seeking asylum in the UK to avoid the provisions of sharia law that give fathers or other male family members the exclusive custody of children over seven.

In the most high-profile UK criticism of the family law provisions of sharia law so far, the Lords stated that these provisions breached the mother's rights to family life and the right against discrimination and were severely disruptive to the child.

The comments followed months of debate over the appropriateness of incorporating sharia courts into the UK's legal system.

Such a move has been advocated by figures including the Archbishop of Canterbury, Rowan Williams, and Lord Phillips, the new senior law lord.

The minister for community cohesion, Sadiq Khan, a Muslim, said recently that sharia courts risked entrenching unequal bargaining power between the sexes.

Sharia courts have been delivering judgments in the UK since last year, and currently operate in London, Birmingham, Bradford, Coventry and Manchester, with plans to expand into Scotland.

Formally classified as arbitration tribunals, their decisions are legally binding and can be enforced by county courts and high courts provided that both sides in a case agree to have the matter decided under the sharia system.

One of the most controversial areas in which the network of sharia courts is already operating is family law, including divorce and domestic violence.

Ruling that the woman should not be returned to Lebanon, Lord Hope said "the mutual enjoyment by parent and child of each other's company is a fundamental element of family life".

"The fact is, however, that sharia law as it is applied in Lebanon was created by and for men in a male-dominated society," he added.

"The place of the mother in the life of a child under that system is quite different under that law from that which is guaranteed [by the European convention on human rights] ... it is discriminatory, too, because it denies women custody of their children after they have reached the age of custodial transfer simply because they are women."

Lord Bingham, a former senior law lord, added that, as a result of the provisions, "women are often constrained to remain in abusive marriages for fear of losing their children".

He criticised the provisions of sharia law for automatically giving custody to "a father who has inflicted physical violence and psychological injury on the mother".

Although the court, which ruled 5-1 that the woman and her son should be allowed to remain in the UK, said the case was "exceptional", it is anticipated that the decision will set a precedent for future cases.

The human rights group Liberty, which intervened in the case, said the ruling "upheld basic protections which must be available to us all".