David Cameron is allowing senior Cabinet ministers to back an EU referendum Bill and vote against the Queen’s Speech.
Eurosceptic MPs will next week force a vote condemning the Queen’s Speech for failing to include legislation on a referendum.
The Prime Minister will be on a visit to the US but he has given colleagues a free vote on the issue.
Eurosceptic ministers including Work and Pensions Secretary Iain Duncan Smith, Environment Secretary Owen Paterson, and even Foreign Secretary William Hague, are among at least 100 Conservatives who may support the move, sources said.
Labour leader Ed Miliband will today announce that Labour will not back an in/out referendum on Europe, in a move that will dash the hopes of many of his own MPs who think he should match Mr Cameron’s pledge to hold a referendum after the next election.