Cameron faces mutiny over Lords reform David Cameron is facing the biggest Conservative rebellion since the election and a severe test of the coalition, after a mutiny by some of his MPs against plans to introduce elections to the House of Lords. At a highly charged private meeting on Thursday, dozens of Tory MPs warned they would vote against the reforms - the centrepiece of next month's Queen's Speech. But Mr Cameron has promised Nick Clegg, deputy prime minister, that he will deliver the reforms, seen by Liberal Democrats as the fulfilment of a century-long crusade to reform the upper house. The meeting of the 1922 backbench committee was described by one MP as "stormy." About 40 MPs are said to have spoken against the reforms, with only one newly elected MP, Gavin Barwell, speaking in favour. One parliamentary aide has indicated they would resign in protest if the bill went ahead. Tory MPs said Mr Cameron should stand up to the Lib Dems and ditch a bill which they argue could lead to parliamentary gridlock, cause divisions in the party and prove a major distraction when the coalition should be focusing on the economy. There were also concerns that the reforms - expected to feature an 80 per cent elected upper house with 15-year terms - could challenge the supremacy of the House of Commons and leave the Lib Dems holding a permanent balance of power in the new chamber. Mr Cameron is caught in a vice between an increasingly restive Tory party - battered by weeks of negative post-Budget reaction and frustrated by life in coalition - and Mr Clegg, who expects the prime minister to stand firm. On Thursday night Downing St insisted: "Lords reform was in our manifesto and the manifesto of the other two parties. It was a crucial part of the coalition deal. We are not planning to let this blow us off course. Tory strategists hope the estimated 60-70 Tory MPs at the meeting do not represent opinion in the whole party. But Mr Cameron could well see a greater rebellion when the bill is presented than the 81 dissenters who defied the party whip over Europe. In theory, the government could try to push the bill through the Commons with the support of Labour MPs, but that would be a high-risk strategy and cause serious damage to Tory morale. If the bill was wrecked by Tory rebels, Lib Dems could retaliate by killing Mr Cameron's cherished boundary review for the Commons: the prime minister's plan to cut the number of MPs from 650 to 600 is seen by the Tory high command as a means of securing a majority at the next election. "It is really explosive, it is the holy grail of the Liberal Democrats," said one Tory MP. They are not going to get Lords reform and we are not going to get the boundary review. This is a game changer. The coalition is not going to last until 2015. One "very loyal" Tory backbencher said: "The leadership tries to claim an elected second chamber would not damage the primacy of the Commons, but of course it will. If we do this, it will damage the faith the markets have shown in us. One reason investors trust us is that we're able to get things through without deadlock.