A new ComRes survey of 159 MPs, conducted over the past month, has found overwhelming parliamentary support for the amendment to the Marriage (Same Sex Couples) Bill, championed by Tim Loughton MP, which would extend civil partnerships to opposite sex couples.

The poll found that more than seven in ten MPs from all main parties support extending civil partnerships to opposite sex couples.

A separate public poll suggests support for same-sex marriage could be affected if the Government’s proposals to legalise same sex marriage is not seen to be ‘equal’ in their treatment of opposite sex couples by failing to extend civil partnerships. The poll found that more than six in ten people who supported legalising same sex marriage said they would support it ‘only if couples of the opposite sex also get the right to enter into a civil partnership if they wish’.

Tim Loughton MP, who is backing the amendment to extend civil partnerships, said: “This comprehensive poll clearly shows there is strong cross support to address the inequality that would result from marriage being available to same sex couples if the Bill goes through. Far from being a ‘wrecking measure’ some of the strongest support for my amendment to extend civil partnerships comes from the biggest supporters of same sex marriage in the Labour and Lib Dem parties.

“If the Government think it is right to extend marriage to everyone then it has to be right to extend civil partnerships to everyone too. This can only be good for improving stability for many more of the near 3 million opposite sex couples who currently choose to cohabit but are in no formally recognised relationship. Giving them the opportunity for the rights and responsibilities that go with civil partnerships has also to be a good thing for more stability for children which is enormously important at a time of rising family breakdown.”

Andrew Hawkins, Chairman of ComRes, said of the findings: “The mood in Westminster is very clear: at least seven in ten MPs of every main party support extending civil partnerships to opposite sex couples, whether or not in conjunction with same sex marriage. Moreover, public supporters of gay marriage appear to consider this issue very important to their continued support. If civil partnerships are not extended to opposite sex couples, there could be a risk of yet more voter backlash but ironically this time from supporters rather than opponents of gay marriage.”

On Thursday, PinkNews.co.uk revealed that the government intends to review the future of civil partnerships exactly five years from the point when the same-sex marriage bill comes into law for England and Wales.

It opens the door for the possible extension of civil partnerships to heterosexuals – something which Culture Secretary Maria Miller ruled out as current government policy on Tuesday.

One peer who won’t be backing the policy is the Archbishop of Canterbury, who on Friday did a u-turn on his previous pledge to support opening up civil partnerships.