More than half of Britons now want to leave the European Union, according to an opinion poll carried out after the Paris attacks for the Independent newspaper.

The ORB survey of 2,000 people showed 52 per cent of British voters wanted to leave while 48 per cent wanted to stay. In similar polls in June, July and September, a majority had wanted to stay in the EU.

Earlier this month, British Prime Minister David Cameron launched his attempt to reform the 28-member bloc ahead of a referendum on whether Britain should remain an EU member, a vote which he has promised will take place by the end of 2017.

A British divorce would shake the bloc to its core, ripping away its second largest economy and one of its top two military powers. Pro-Europeans warn an exit from the EU would hurt Britain's economy and could trigger the break-up of the United Kingdom by prompting another Scottish independence vote.

Other polls have shown British support for staying in the European Union fell this year as an influx of migrants into Europe raised concerns about membership.