David Cameron faces defeat in bid to halt Tory revolt over elected Lords Another "concession" is that the primacy of the House of Commons will be firmly spelt out in the legislation, leaving no room for doubt. It was hoped both measures would reassure Tory MPs that the reforms, the pet project of Mr Clegg, would not seek to establish the new chamber as a powerful rival to the Commons. However, a Downing Street source reaffirmed that there would definitely not be a referendum on the reform plans. The source also signalled no retreat on the broad thrust of the plans by insisting they would be taken forward in a Government Bill reinforced by a three-line whip, effectively an instruction to all Conservative and Lib Dem MPs to vote for it. Last night Simon Hart, the Conservative backbencher, said: "If these are the concessions that are on offer, I think somebody, somewhere, doesn't really understand what the real problem is. The principle to which we are objecting is that of an elected second chamber. The best way of ensuring someone has no power is not to elect them in the first place. It seems to be that this being done not with the interests of the voter in mind, but for Coalition managements reasons. I don't take any pleasure in it - I don't like voting against the Government. With scores of backbenchers set to rebel, Conservative ministers are also increasingly voicing opposition to the plans in private - with Owen Paterson, the Northern Ireland Secretary, and Iain Duncan Smith, the Work and Pensions Secretary, said to be the leading opponents of the plan inside the cabinet. The rebellion over Lords reform could eclipse what is currently the biggest backbench revolt since the last general election - when 81 Tory MPs defied the Government in a vote on holding a referendum on Britain's membership of the European Union last October. That vote also saw two Conservative parliamentary private secretaries - Stewart Jackson and Adam Holloway - leave their posts. Numbers could be higher this time round with some Tories putting the potential rebels at more than 100. Tory anger has been fuelled by the decision by the Liberal Democrats not to back Jeremy Hunt, the embattled Culture Secretary, in a Commons vote earlier this month calling for Mr Hunt to be investigated over his stewardship of News Corporation's bid for BSkyB. The measure has to be debated at all stages on the floor of the Commons, which means that the government's entire legislative programme could be "gummed up" for months or even years. To wreak maximum havoc, Tories could vote down a "programme motion" when the Bill is debated in the week before the Commons rises for the summer recess on 17 July. If ministers lose the programme motion vote they will also lose the power to limit debate on the bill by imposing "guillotine" motions. Labour hit out at the Government for ruling out a referendum. Sadiq Khan, the shadow justice secretary, said: "Labour is committed to a wholly elected second chamber fit for the demands of a modern democracy. Our goal is clear but we have the humility to trust the public. Fundamental changes to our constitution should be put to the people in a referendum. The Government is showing breathtaking arrogance. Lords reform is no different in this respect to devolution in Wales, Scotland and London, a regional assembly in the North East, mayors in towns and cities up and down the country and changes to our voting system, all subject to referendums, some won and some lost.