UK has one in six chance of exiting the Eurozone, study

David Cameron setting out the Conservative Party's manifesto theme at the Saga offices in Hastings, Kent.

The measure, drawn up by thinktank OpenEurope, put the chances of the UK quitting Europe at 17 per cent, with an overwhelming 83 per cent likelihood it will stay.

A poll carried out for OpenEurope found that 41 per cent of voters would opt to quit the EU and just 37 per cent to stay in if a referendum was held under the current terms of membership. But positions were reversed - with 47 per cent voting to remain and 32 per cent to leave - if the 28-nation bloc was successfully reformed.

But the thinktank said its barometer took into account not only the state of public opinion on the issue, but also the question of what government will emerge from the May 7 general election, the likelihood of that government holding a referendum and the potential outcome of an in/out vote. It also factors in how strongly the next government will push for EU reform and how open and willing the rest of the EU is to reform.

The Barometer found that the greatest likelihood of an in/out referendum during the next Parliament would come if Tories win an absolute majority on May 7, and said there was a 48 per cent chance of Britain voting to leave if David Cameron gets the opportunity to hold the referendum he has promised for 2017.

But it deemed this election result less likely (16 per cent) than a minority government of Tories or Labour (both 18 per cent), a Conservative/Lib Dem coalition (20 per cent) or a Labour/SNP pact (17 per cent), all of which would reduce the chances of a referendum being held.

By the Barometer’s calculations, the most likely scenario for Brexit is a Tory/Lib Dem coalition - with a 20 per cent probability of this being the election outcome and an 85 per cent chance of such a government pressing ahead with a referendum - and the least likely a Labour/Lib Dem partnership, seen as a 13 per cent probability to form a Government but just a 5 per cent chance to stage a vote.

The Barometer will be regularly updated to reflect shifts in sentiment, with the aim of acting as a “bellwether” for the health of the UK’s relationship with the EU, said OpenEurope.