The head of a Christian advocacy group says Christians must resist attempts to broaden the definition of marriage to include same-sex couples in civil partnerships.

Andrea Minichiello Williams, barrister and director of Christian Concern For Our Nation, has expressed concern over comments made this week by Deputy Liberal Democrat leader Simon Hughes.

Mr Hughes, who is a Christian and admitted previously to being bisexual, said he believed the Government would make it possible for the term ‘civil marriage’ to apply to same-sex couples before the next General Election.

The move would give them the same legal and social status as heterosexual married couples, although he contended that faith groups could choose which status they wanted to give same-sex couples in a civil union.

“It would be appropriate in Britain in 2010, 2011, for there to be the ability for civil marriage for straight people and gay people equally,” he said.

He added: “That’s different of course from faith ceremonies which are matters for the faith communities ... they have to decide what recognition to give.”

“The state ought to give equality. We’re halfway there. I think we ought to be able to get there in this Parliament.”

The law at present gives same-sex couples who enter into civil partnerships similar rights to heterosexual married couples but stops short of according the same symbolic status to their union.

Ms Minichiello Williams said: “We should resist this attempt to undermine marriage at the heart of our society and fight to retain the traditional status of marriage as that between a man and a woman.”

Earlier in the month, Equalities minister Lynne Featherstone said the Government would consider allowing same-sex couples to have religious readings, music and symbols at their civil partnership ceremonies.

The last Parliament already voted through an amendment to the Equality Act that made it possible for civil partnership ceremonies to be held on religious premises and the Government is to begin a consultation with members of the LGBT community on further reform to civil partnership laws.

In the run-up to the General Election, the Conservative Party pledged to consider giving gay couples the same marriage status as heterosexual couples. Lib Dem leader Nick Clegg is a strong supporter of equal marriage status.

Attempts to further liberalise the laws have been met with strong opposition from Tory traditionalists.

Lord Tebbit said: “I wouldn’t want anything done to add to the pretence that a civil partnership is a marriage.”