Coalition will bring in gay marriage despite Tory resistance, vows Clegg

Clegg: 'Many other countries have taken this progressive step and I think it's about time Britain joined them'

Nick Clegg has given a firm promise that the Government will bring in a law to allow gay marriage despite a growing campaign by Conservative MPs to derail it. In a warning shot across the bows of Tories who oppose the move, the Deputy Prime Minister declared that it is a matter of "how, not whether" same-sex marriage is legalised.

A dispute between Liberal Democrat and Tory MPs has broken out after both parties suffered heavy losses in this month's council elections.

Tory backbenchers have urged ministers to shelve gay marriage legislation and House of Lords reform – both flagship Lib Dem policies – so the Government can focus on bread-and-butter issues such as the economy, which they claim matter more to many voters.

Yesterday Owen Paterson, the Conservative Northern Ireland Secretary, became the first Cabinet member to declare that he would oppose the move.

In a letter to a constituent, he said: "Having considered this matter carefully, I am afraid I have come to the decision not to support gay marriage."

More than 520,000 people have signed a petition from the Coalition for Marriage, which leads the campaign against same-sex weddings. Mr Clegg, by contrast, has signed a petition organised by the rival Coalition for Equal Marriage, which is lobbying for change.

Mr Clegg told the pro-equal marriage group: "The Coalition Government, the Liberal Democrats and I remain wholeheartedly committed to lifting the ban on equal civil marriage. We are currently consulting on how, not whether, to introduce proposals for equal marriage and I want to encourage everyone to make sure that their voices are heard during this time."

David Cameron has made a strong personal commitment to introducing gay marriage legislation. But the Lib Dems are worried that some Tory ministers may try to reopen the issue under pressure from the party's MPs. "The idea that this was an issue on the doorstep in the local elections is nonsense," said one Lib Dem source.