A BILL to legalise gay marriage was rescued by a last-gasp deal with Labour last night - but at the risk of further inflaming Tory anger with David Cameron.

The Coalition reached agreement with Ed Miliband to defeat what ministers had branded a "wrecking" amendment, designed to allow men and women to have civil partnerships.

The move would have triggered complicated, and hugely expensive, pension and other rights, ministers claimed - costing up to £4bn and forcing a two-year delay.

On a day of drama, the Coalition agreed to back a Labour amendment to hold an immediate review into extending civil partnerships to all - without derailing gay marriage.

It means the first same-sex weddings - including ceremonies in some churches that agree to host them - are likely to take place as early as next summer.

But Mr Cameron's decision to turn to Labour for help seemed certain to spark further grassroots Conservative fury with No.10, after a tumultuous week.

Many party members already see the prime minister as badly out of touch - a row intensified by alleged comments from an ally of his labelling Tory activists as "mad, swivel-eyed loons".

Conservative co-chairman Lord Feldman has denied making the remarks.

To add to Tory nerves, one poll, last night, put the party at a record low of 24 per cent - just two per cent head of UKIP. Labour was on 35 per cent.

On Sunday, more than 30 present and former local party chairmen warned Mr Cameron's backing for gay marriage was driving Tory voters to defect to UKIP.

Last night 70 MPs backed an amendment, brought forward by ex-minister Tim Loughton, to extend civil partnerships to heterosexuals - far fewer than the 100-plus anticipated by some critics.

It was defeated by a majority of 305 votes.

Furthermore, last night, it seemed far from certain that the review would lead to an extension of civil partnerships - or that any further change will be introduced quickly.

There were suggestions that the review could result in such legal rights - introduced by Labour, for gay couples, in 2005 - being scrapped altogether.

And one Conservative source hinted it would be kicked into the long grass, vowing that, while it might be "immediate", it would be "'very thorough and very, very long"

Two of the region's Tory MPs James Wharton (Stockton South) and Anne McIntosh (Thirsk and Malton) - both gay marriage opponents - were split on extending civil partnerships.

Mr Wharton said: "It should remain an option, but I'm concerned about the cost of it, the lack of detail and the fact that this idea came forward at the last minute.

"The Bill will now have this provision for a consultation on this, so I don't see the need to legislate for it."

But Ms McIntosh said: "Yes, I support extending civil partnerships to heterosexual couples."

However, the Church of England is opposing civil partnerships for all, saying: "We believe this would introduce further confusion about the place of marriage in society."

In February, MPs voted to legalise gay marriage with a whopping majority of 225 - despite most Tories refusing to support the move.

The Marriage (Same Sex Couples) Bill has now returned for debate on the details. It should clear the Commons tonight (Tues), before heading to the Lords, where stiff resistance is certain.

Earlier, Culture Secretary Maria Miller urged MPs not to risk a two-year delay. She said: "I want to be seeing the marriages undertaken under this new Bill as early as next summer."

The danger for Mr Cameron is that he will now receive little credit for forcing through gay marriage, even amongst the Bill's supporters.

The polls repeatedly show that - like the apparent Conservative obsession with EU membership - few people think the issue is among the most important facing the country.