MPs have urged peers to throw out the same-sex marriage Bill on Monday, saying that the free votes in the Commons were a sham.
In a joint letter, a group of 15 MPs told members of the House of Lords that although the main parties claimed to have allowed MPs to vote with the consciences in reality pressure was placed on them to vote in favour of the controversial legislation.
The signatories said that MPs were threatened with the ruin of their careers if they opposed Marriage (Same-Sex Couples) Bill.
“The main parties announced a free vote but we saw varying degrees of coercion with threats made, for example, to an MP’s future political career or withdrawal of party support at future elections,” said the letter, which was signed by Catholics Edward Leigh, Therese Coffey and Jim Dobbin.
“Regrettably, our ability as MPs to oppose, amend or scrutinise this Bill was heavily constrained,” they said.
According to a national newspaper, some backbench Conservative MPs say they were strongly advised by Ministers not to oppose David Cameron, the Prime Minister, who is determined to redefine marriage to include same-sex couples.
The Conservative Party has denied issuing threats to MPs but a poll by ComRes showed that almost three in 10 Tories and one in 10 Labour MPs did not believe they had a free vote.
During the Third Reading of the Bill in the House of Commons a total of 130 Conservatives rebelled.
The Bill, which was not included in the election manifesto of any of the main parties and faces huge public opposition, is expected to be the subject of further rebellions in the Lords when it arrives there on Monday.
The Catholic Church and the mainstream Anglican and Protestant denominations as well as Muslims, Jews, Hindus and Sikhs are all opposed to the Bill.
The Catholic Church has sought amendments, warning the Government of the harm the law would inflict on Catholic education and the rights of individuals to worship God in keeping with their consciencies.
But one Anglican bishop has now voiced his support for the proposals.
In a letter to the Daily Telegraph, Nicholas Holtam, the Bishop of Salisbury, compared the existing prohibition of gay weddings to the acceptance of slavery by some Christians before abolition.
“Christians have had to rethink the priorities of the Gospel in the light of experience,” he said.
“For example, before Wilberforce, Christians saw slavery as Biblical and part of the God-given ordering of creation … the Biblical texts have not changed; our interpretation has.”
He added: “The development of marriage for same-sex couples is a very strong endorsement of the institution of marriage.”