The Government will "listen very carefully" to Liberal Democrat demands for gay marriage to be legalised, equalities minister Lynne Featherstone said today.
The Lib Dem minister said she could "hear the growing call" for same-sex couples to be given the same right to a wedding as mixed-sex couples.
At the party's conference in Liverpool, Liberal Democrats overwhelmingly backed a motion to allow same-sex and mixed-sex couples to choose whether they wish to have a marriage or civil partnership, and to allow gay couples to have a church wedding.
Ms Featherstone said: "I'm proud of the Liberal Democrats overwhelmingly supporting this motion. It underlines our fundamental commitment to equality and fairness.
"As minister for equality I hear the growing call for same-sex marriage and I believe that as a Government we must listen very carefully to that message."
During the debate at the conference the motion's supporters were keen to stress that religious groups would not be forced to conduct marriage ceremonies for gays if it went against their beliefs.
Lib Dem MP Stephen Gilbert acknowledged the motion was controversial, telling the conference: "Of course, there will be opponents. When it comes to equality, you and I all know that there are opponents.
"But let's be clear. This motion doesn't compel religious groups to offer gay marriage or compel gay people to get married. It simply extends an equal choice to one and all."
The debate was led by former MP Evan Harris, who said it would give the Lib Dems in Government, including Ms Featherstone, the right to press for a change in the law.
Dr Harris said there had been a "remarkable transformation" in the Conservative Party in recent years, "but we need to test that new Tory commitment to equality and this one of the areas where we can help Lynne do that".
The former Oxford West and Abingdon MP said: "We should seize the moment to push the agenda forward on full equality.
"We have never failed to do that in the past. There's plenty of work still to do. Let's give Lynne and other Liberal Democrats in Government something to get their teeth into."
The conference agreed to the opening up of marriage and civil partnerships to both same-sex and mixed-sex couples.
The motion would allow religious and humanist celebrants to legally solemnise and celebrate same-sex marriages and civil partnerships in places of religious worship.
It would also allow people who change sex to remain in their current marriage or civil partnership.
Gay couples married outside the UK would have their relationship automatically recognised in the UK.
This change would apply to former London mayoral candidate Brian Paddick, who told the conference he married his partner in Oslo in an "intensely moving" ceremony.
He told the conference: "We are married. It is important. Yet we are only married in Norway. Here it reverts to a civil partnership and that doesn't feel the same at all.
"Yes, we have to be sensitive to religions and what they feel on this issue, and we are not talking necessarily about forcing religions to marry same-sex people in their synagogues and churches and temples.
"But what we are saying is that there should be equality. If I want to marry my same-sex partner then I should be allowed to do that."
Ed Fordham, who failed to win the Hampstead and Kilburn seat at the General Election, said: "The marriage laws are 200 years out of date and we have the responsibility to drag them out of the closet."
Fred Dunford, from Meon Valley, Hampshire, was one of a handful of party members at the conference to oppose the motion, arguing it would cost the Lib Dems votes on the doorstep.
"Civil partnerships give enough legal protection and in tax and inheritance rights. I do not believe that we should go as far as marriage."
He added: "Consider your own constituents, your own voters and what they feel."