The Church of England has effectively accepted defeat over gay marriage signalling that it will no longer fight against a change in the law.
In a short statement, the established Church said that the scale of the majorities in both the Commons and Lords made clear that it is the will of Parliament that same sex couples “should” be allowed to marry.
The Bishop of Leicester, who leads the bishops in the House of Lords, said they would now concentrate their efforts on “improving” rather than halting an historic redefinition of marriage.
It represents a dramatic change of tack in the year since the Church insisted that gay marriage posed one of the biggest threats of disestablishment of the Church of England since the reign of Henry VIII.
And it comes despite a warning from the Archbishop of Canterbury, the Most Rev Justin Welby, that the redefinition of marriage would undermine the “cornerstone” of society.
The climb-down comes as the newest diocesan bishop in the Church of England said that support for gay marriage was “understandable” because of the way gay people had been treated in Britain in the past.
The Rt Rev David Walker, who was named today as the new Bishop of Manchester, insisted that although the Government bill was “flawed” had he been in the House of Lords he would not have voted against it.
Peers voted by 390 to 148 against a motion which would have struck down the Government’s same-sex marriage bill on Tuesday.
It will now be scrutinised by peers who are likely to add a series of amendments to add extra protections for teachers or other workers who object on grounds of conscience.
In a statement, Rt Revd Tim Stevens, Convenor of the Lords Spiritual, said bishops would now “join” with politicians to strengthen parts of the bill rather than resisting it.
“Both Houses of Parliament have now expressed a clear view by large majorities on the principle that there should be legislation to enable same-sex marriages to take place in England and Wales,” he said.
“It is now the duty and responsibility of the Bishops who sit in the House of Lords to recognise the implications of this decision and to join with other members in the task of considering how this legislation can be put into better shape.”
And he made clear that the bishops would look not only at strengthening opt-outs for those who oppose a new definition of marriage but at the future practicalities for people in same-sex unions.
He signalled that bishops would seek to introduce a notion of adultery into the bill and extend parental rights for same-sex partners.
Under the current bill people in a same-sex marriages who discover that their spouse is unfaithful to them would not be able to divorce for adultery after Government legal experts failed to agree what constitutes “sex” between gay or lesbian couples.
The bishops are also seeking to change a provision which says that when a lesbian woman in a same-sex marriage has a baby her spouse is not also classed as the baby’s parent.
The result is that in some cases children would be classed as having only one parent.
Bishop Stevens said: “The concerns of many in the Church, and in the other denominations and faiths, about the wisdom of such a move have been expressed clearly and consistently in the Parliamentary debate.
“For the Bishops the issue now is not primarily one of protections and exemptions for people of faith, important though it is to get that right, not least where teaching in schools and freedom of speech are concerned.
"The bill now requires improvement in a number of other key respects, including in its approach to the question of fidelity in marriage and the rights of children.
“If this bill is to become law, it is crucial that marriage as newly defined is equipped to carry within it as many as possible of the virtues of the understanding of marriage it will replace.
“Our focus during committee and report stages in the coming weeks and months will be to address those points in a spirit of constructive engagement."
His comments came as the new Bishop of Manchester signalled sympathy with supporters of gay marriage.
In his first comments since he was named as replacement to Rt Rev Nigel McCulloch, who recently retired, he said that the bill was flawed but added: “I fully understand why in a society where for so long gay people have been subjected to such abuse and ill treatment many people say if they are asking for equality in the area of marriage that is something they can get.”
He added: “I can see why in our society many people now – the majority of people – think that if this will help them to feel less badly treated then let them have it.”
Bishop Walker, who is currently the Bishop of Dudley – a junior bishop in the diocese of Worcester – attracted headlines earlier this year when he took on David Cameron over welfare cuts and accused politicians of scaremongering over immigration.
It emerged last month that Manchester Diocese, one of the biggest dioceses in the Church of England, had included a requirement to foster better links with the city’s lesbian, gay, bisexual, and transgender communities as part of its new bishop’s job description