Ken Clarke warns against EU exit

Tory big beast Ken Clarke has joined forces with Liberal Democrat Danny Alexander and Labour's Lord Mandelson to warn that leaving the EU would be an "historical error".

The politicians insisted the UK should work to reform the organisation from within rather than walking away.

The intervention came as the cross-party British Influence group launches a manifesto titled Better off in a Better Europe.

After David Cameron pledged an in-out referendum on membership by 2017, the document warns against threatening "unilateral repatriation of powers".

But it also concedes that the EU must be "rebooted for the 21st century" and Treaty change is "inevitable", arguing that control should be returned to member states in some areas.

Mr Clarke, regarded as the sole Conservative europhile in the Cabinet, said: "This is a compelling and practical manifesto for a reformed Europe focused on growth and competitiveness. David Cameron has already shown what can be achieved in Europe through strong, determined leadership. This document brings out the huge further rewards the British can reap by remaining doggedly engaged in Europe, and determined to help set the agenda.

"We earn our living in a globalised economy and a world in which nations are interdependent in tackling global and regional problems. We can help to promote our own interests best by reinforcing our role as a leading nation in the EU."

Treasury minister Mr Alexander said: "Membership of the EU gives market access to British firms, makes us more attractive to overseas investors, and underpins more than three million British jobs.

"EU trade deals with the US, India, Canada and Japan will be worth billions to the UK economy but could not be won by the UK alone. Britain must work with our allies for change from within to ensure the EU continues to take reform seriously. The isolationists are reckless with our prosperity and security. We cannot let them succeed."

Former business secretary Lord Mandelson said: "If Britain quit the EU amongst the losers would be businesses foregoing trade and investment opportunities, their employees whose jobs and workplace rights would be at risk, the police and security agencies who would sacrifice vital collaboration and the British people who would lose the freedom to travel, live and work as they wish across Europe. In return we would get the dubious satisfaction of standing alone in the world."