A British lesbian couple married lawfully in Canada will challenge the UK’s gay marriage laws in the High Court tomorrow.

University professors Sue Wilkinson and Celia Kitzinger were married lawfully in Canada in August 2003, while Sue was working there, after the province of British Columbia opened up marriage to same-sex couples.

Their marriage is fully recognised in Canada, but the UK’s Civil Partnership Act says that same-sex couples who legally marry overseas “are to be treated as having formed a civil partnership”. Sue and Celia want the UK to recognise their marriage as a marriage, not as a civil partnership.

Their legal case is part of an international movement to secure the global recognition of Canadian same-sex marriages. In Ireland, another lesbian couple married in Canada, Katherine Zappone and Ann Louise Gilligan, are mounting a similar legal challenge in the Irish courts There are also challenges pending in Israel, New Zealand and Hong Kong.

The human rights organisation, Liberty is providing pro bono legal representation and advice. The lead barrister is Karon Monaghan of Matrix Chambers.

“A different-sex couple married in Canada would automatically have their marriage recognised as a marriage in the UK. We believe that to operate a different set of rules for same-sex couples is profoundly discriminatory – an affront to social justice and human rights,” said Sue Wilkinson.

“We are bringing a test case to the High Court in London, with the support of the human rights watchdog, Liberty, who are providing legal representation; and with the backing of OutRage!, the lesbian, gay, bisexual and transgender human rights group,” added Celia Kitzinger.

“Our lawyers are seeking a declaration of the validity of our marriage, with reference to the European Convention of Human Rights and the Human Rights Act 1998,” Ms Kitzinger said.

“This is a historic challenge to a grave injustice,” said Peter Tatchell of the gay rights group OutRage!

“It is the first step towards overturning the ban on same-sex marriage in Britain.”

“All other marriages conducted lawfully abroad are recognised in the UK. To refuse to recognise a lawful same-sex marriage is an act of wanton discrimination.

“In a democratic society everyone is supposed to be equal before the law. Refusing to recognise same-sex marriages enacted in Canada is a denial of equality, since opposite-sex Canadian marriages are granted automatic legal recognition in Britain.

“The ban on same-sex marriage in the UK is institutional homophobia. It signals the continuing second class legal status of lesbian, gay and bisexual people.

“The government’s position is that same-sex marriages conducted abroad are accorded the status of civil partnerships within the UK. This is unacceptable.

“Civil partnerships are not equality. They are sexual apartheid, with one law for heterosexuals, marriage, and another law for gays, civil partnerships.

“The homophobia of the ban on same-sex marriage is compounded by the heterophobia of the ban on opposite-sex civil partnerships. Two wrongs don’t make a right.

“Civil partnerships are second best. Nothing less than marriage equality is acceptable,” said Mr Tatchell.