An alliance of religious leaders has also warned in a letter that same-sex marriage will “devalue the meaning of marriage”. Christian, Jewish, Muslim, Hindu and Buddhist leaders, including Bishop Michael Hill, the Anglican Bishop of Bristol, and Sir Iqbal Sacranie, a former head of the Muslim Council of Britain, all urged Mr Cameron to rethink the legislation.
Same-sex marriage sets a "dangerous precedent" which could lead to sibling marriage or polygamy, says Lord Carey.
He has previously courted controversy by likening critics of gay marriage to persecuted Jews in Nazi Germany. Gay rights group Stonewall said the comments were "regrettable" and accused the peer of "hyperbolic shroud waving".
Lord Carey has been a vocal opponent of the government's Marriage (Same Sex Couples) Bill for England and Wales, which will be debated by peers on Monday
Lord Mackay was asked at an event hosted by the Theos think tank whether, in light of the Church of England’s opposition, signing the Bill might put the Queen in breach of her Coronation Oath. Lord Mackay, who opposes same-sex marriage, said that ministers should ensure any legislation was consistent with the Queen’s promise.
He said: “The Queen under our constitutional arrangements is expected to act in accordance with the advice of her ministers, given ultimately through the Prime Minister.
"The idea of the Coronation Oath was that it would never be in conflict with that advice and therefore it is the responsibility of the ministers of the Crown to see that whatever advice they give is consistent with the proper construction of the Coronation Oath.”