Eurosceptic Conservative MPs are to demand that David Cameron overrules Nick Clegg and ensures the Government grabs back some powers from Brussels before the next election.
The Fresh Start group, which has the support of 120 Tory MPs, is drawing up a "shopping list" of functions that should be handed back to the UK by the European Union.
They could include control of employment laws; health and safety measures; farming and fishing; justice and crime; and structural funds for poor areas. The group's demands will be set out in an alternative "White Paper" in July. The move shows that Tory MPs, while welcoming Mr Cameron's decision to veto a new EU treaty designed to rescue the euro, will press him to go further - even though that would increase tensions with the Liberal Democrats and Britain's UK partners.