Ministers challenge churches over gay marriage

She signalled the Government’s determination to make the change by 2015, at an expected cost of £4m, putting Ministers on collision course with church leaders and many Conservatives.

Tory MPs are expected to be offered a free vote when legislation championed by Prime Minister David Cameron comes before the Commons in a bid to prevent an embarrassing backbench revolt.

Under the plans put out for consultation yesterday, same-sex couples will be entitled to get married in register offices or other civil ceremonies, or convert existing civil partnerships.

Existing marriages in which one partner has changed sex would also no longer have end.

The proposals, also endorsed by home Secretary Theresa May, will keep a legal ban on same-sex religious services despite some churches expressing an interest in conducting them.

Nor do they anticipate allowing heterosexual couples to enter civil partnerships, the state-recognised partnerships introduced in 2005 as a first step towards gay marriage.

In a joint foreword, the two Ministers said the present discrimination was unacceptable. They wrote: “Put simply, it’s not right that a couple who love each other and want to formalise a commitment to each other should be denied the right to marry.”

The reforms have provoked religious fury, with the UK’s most senior Catholic branding them a “grotesque subversion of a universally acknowledged human right”.

Many Tory MPs are also known to be hostile to a change seen as an example of Liberal Democrat influence on coalition policy despite Mr Cameron’s public support.

Half the party’s grassroots supporters are against the change, a recent poll suggested, though it was backed by a margin of 45 per cent to 36 per cent among the wider public.

However, whips look set to treat the issue as a matter of conscience when it is debated in Parliament amid fears of a major revolt.