David Cameron today promised an in/out referendum on the UK's membership of the European Union by the end of 2017 if the Conservatives win the next general election.

In a major speech in London, Mr Cameron said that the Conservative manifesto for the 2015 general election will ask for a mandate to negotiate a "new settlement" for Britain in Europe, which will be put to voters in a referendum within the first half of the five-year Parliament.

But the Prime Minister said he will campaign "with all my heart and soul" for Britain to stay in the European Union when the referendum comes.

And he warned voters that if the UK did decide to leave, it would be "a one-way ticket, not a return".