Churches 'could be sued for refusing to agree to gay marriages' Other legal opinions commissioned by opponents have argued that teachers could face disciplinary measures under equality laws if they refuse to promote same-sex marriage once the change has been implemented. Lord Carey warned the plans will lead to "serious and wide-ranging conflict between religious institutions and local authorities." He also argued that the legal opinion "demonstrates why the legislation is unworkable." He concluded: "These proposals are divisive, have no mandate and are poorly thought-out." Same-sex marriage has been fast-tracked by David Cameron despite strong opposition within his party and from some religious groups. Earlier this month more than 1,000 priests - a quarter of all Catholic clergy in England and Wales - signed a letter to The Daily Telegraph arguing that the change could open the door to new discrimination against Christians. The moves signal the start of a string of new "grassroots" protests organised independently of the Church hierarchy in the run-up to the publication of the Government's Equal marriage Bill, within weeks. A House of Commons vote on the bill is planned before mid-February. Ministers expect the legislation to take up to 12 months to get through Parliament. Conservative Party MPs, including ministers, will get a free vote amid private fears that at least 40 per cent of Tory MPs oppose the plans. Labour has also granted its backbenchers a free vote, in a surprise move. Today, government sources dismissed the warnings. "It is precisely because the Church of England has a legal duty to marry that we have created a legal lock to ensure this doesn't apply to same-sex couples," a Government source told the newspaper. A Downing Street source added that the Prime Minister would "press ahead" with the plans over the next month. They added that No 10 "has legal advice of our own."