THE European Union has been branded an economic "corpse" as more pressure from Conservative backbenchers was piled on David Cameron to hold an in-out referendum on Britain's membership.

The Tory euroscepticism came during a Commons debate when an attempt to pass legislation that would enable the UK to leave the EU failed because it ran out of time.

Conservative backbencher Douglas Carswell said a recent poll found a majority of voters wanted Britain to quit the EU with 51% in favour of leaving and only 34% wanting to stay in.

"This is the highest level of discontent for a generation," declared the MP for Clacton in Essex.

Even members of the Cabinet had started to come round to the view that "Britain may indeed be better off out," argued Mr Carswell.

He told MPs Britain had joined the Common Market believing it would be good for the economy, but the growth of countries such as China and Brazil, coupled with the eurozone crisis, meant "far from joining a rising economic powerhouse, we have shackled ourselves to a corpse".

Mr Carswell insisted withdrawal from the EU could no longer be dismissed as unthinkable. "It's no longer a marginal view confined to mavericks; it is a legitimate point starting to go mainstream."

Fellow Tory Edward Leigh insisted there was a "democratic deficit" as there had been no public vote on membership of the European club since 1975.

Another Conservative, Philip Hollobone, warned of a fresh wave of immigration caused by the eurozone crisis, which could mean "hundreds of thousands more European Union citizens heading our way".

David Lidington, the Europe Minister, said the UK's membership of the EU was based on a "pragmatic" view of what was in the national interest.

He pointed out successive Tory leaders had concluded that "despite the acknowledged flaws and drawbacks of the European Union", membership was "in the national advantage of the British people in terms of what it gives us through trade, through market access, through attracting foreign direct investment and from increased diplomatic leverage over foreign and security policies".

The Prime Minister has ruled out an in-out referendum on the UK's membership of the EU.