PM under renewed pressure on Europe

Prime Minister David Cameron has came under renewed pressure over Europe, as backbench Conservatives launched a bid to force a vote next week in the House of Commons on demands for a referendum.

Downing Street insisted the PM was "relaxed" about the move, and even hinted that Mr Cameron may be prepared to tolerate ministers lining up behind an amendment tabled by eurosceptics who want legislation on the EU referendum before the general election.

Meanwhile, London Mayor Boris Johnson suggested that leaving the EU would be a "shot in the arm" for Britain's democracy and dismissed as "nonsense" claims that departure could cost up to three million jobs.

Following a series of high-profile interventions from Tory grandees calling for British exit, the prospect of a parliamentary rebellion was seen in Westminster as a fresh blow to Mr Cameron's authority, already undermined by Ukip's successes in last week's council elections.

But the PM's official spokesman insisted that Mr Cameron had "always said he is very happy to look at all ways of strengthening his commitment to an in/out referendum in the next Parliament". Asked whether the Prime Minister would be "relaxed" about ministers supporting the amendment he said: "You are fast-forwarding to a vote next week. The Prime Minister is relaxed about that, I think the implication of that is clear."

The amendment, tabled by Tory MPs John Baron and Peter Bone, does not demand legislation on a referendum, but "respectfully regrets" that no bill was included in the Queen's Speech, which set out the Government's legislative agenda for the coming year.

Mr Baron said its purpose was "to keep the Government focused on this issue" and send a clear message that the demand for a bill was "not going away".

Ukip leader Nigel Farage said: "Another storm is brewing for Cameron. Yet again, he will have to stand in the Commons ahead of his peers and in the media spotlight and be grilled on why he is doing all he can to avoid giving the British people a referendum on Europe."

In a speech in London, the Prime Minister defended his approach of seeking fundamental renegotiation of the UK's EU membership before staging a referendum as "logical, sensible, practical". "I think it is possible to change and reform this organisation and change and reform Britain's relationship with it," said the Prime Minister.

Big names from the Conservative past have highlighted divisions over Europe, with former Cabinet minister Michael Portillo following ex-chancellor Lord Lawson in calling for the UK to leave.