Tory MPs likely to defy No 10 as prime minister abandons attempt at compromise ahead of Commons debate David Cameron is bracing himself for the biggest rebellion since he took office, with possible frontbench resignations, when Tory MPs defy No 10 to vote in favour of a referendum on Britain’s EU membership on Monday. As ministers and their aides lined up to tell the chief whip, Patrick McLoughlin, that Downing Street had badly mishandled the debate, No 10 sources indicated that Cameron has abandoned attempts to agree a compromise. Downing Street threw in the towel when George Eustice, the prime minister’s former spokesman who was being lined up by the government to table a “helpful” amendment, defied his former boss. Eustice tabled an amendment calling on the coalition to publish a white paper in the next two years setting out which powers ministers would repatriate from Brussels. The government would then renegotiate the UK’s relationship with the EU and hold a referendum on the outcome. One No 10 source said the prime minister agrees with the Eustice amendment, but cannot support it – and would whip his MPs to vote against it – because it would be unacceptable to the Liberal Democrats. “If the prime minister supported George Eustice’s amendment that would mean the end of the coalition and we would not be holding a referendum. We would be holding a general election.” Eustice indicated on Thursday night that he was “minded” to support the original motion which calls simply for a referendum on Britain’s membership of the EU. Senior Tories said that Downing Street ran into trouble when it imposed a three-line whip on Tory MPs requiring them to vote against a motion, tabled by the Commons backbench business committee, which calls for a referendum to be held on Britain’s membership of the EU. MPs were given the message at a meeting of the 1922 committee at 5pm on Wednesday by a whip who said that the debate would go ahead, as planned, on Thursday next week. Within 30 minutes, a nervous No 10 brought forward the vote by three days, to Monday, to ensure that Cameron and William Hague could be present. By next Thursday, the prime minister and the foreign secretary are due to be in Australia for the Commonwealth heads of government meeting. In a sign of the panic in Downing Street, aides failed to brief key government supporters who had been trying to shore up support for Cameron. One senior figure, who was not told until 7pm on Wednesday, was telling MPs to calm down as he denied reports that the date of the debate had been changed. With increasing numbers of Tory MPs signing up to the motion, one parliamentary aide said he was prepared to resign so he could support the