David Cameron hints at post-election referendum on membership of the European Union

There will be an opportunity after the general election for the British people to give 'fresh consent' to UK membership of the European Union, David Cameron has said (Getty Images)

David Cameron has given the clearest indication yet that the Conservatives will go into the next election with a manifesto pledge to hold a referendum on Britain's membership of the European Union.

In comments, clearly designed to appeal to the right of his party, ahead of his party's conference the Prime Minister said that there would be an opportunity after the general election for the British people to give "fresh consent" to the country's role in the EU.

But he restated his belief that remaining in the EU was in Britain's interests even if the relationship changed as a consequence of the greater economic integration between members of the Eurozone.

Speaking during a round of TV interviews during a visit to Brazil, the PM said it was increasing clear that the status quo was not an option.

"I don't think it is in Britain's interests to leave the EU but I do think what it is increasingly becoming the time for is a new settlement between Britain and Europe, and I think that new settlement will require fresh consent," he said.

"In the next parliament, I think there will be opportunities for a fresh settlement and for new consent to that settlement. There is a reason why. The euro is a currency with 17 different countries. I think, increasingly, one currency will mean one economic policy.

"They are going to change and that will give us opportunities for changing our relationship with Europe.

"I argue for Britain's membership because I want to be able to say to countries like Brazil 'Come to Britain and you can sell to the 320 million consumers across Europe'.

"I argue for Britain's membership because I think it is in our interests. If I didn't think it was in our interests, I wouldn't argue for British membership."

The Government is currently carrying out an "audit" charting what powers that the European Union has over Britain.

Each department has been told to call for evidence on areas for which they have responsibility from "anyone with knowledge or expertise in any area of EU activity".

It is expected to be completed by late 2014 and its findings are likely to make their way into the Conservative manifesto at the next election. It is likely that Mr Cameron would commit to putting any redrawing of powers to a referendum - possibly including a straight in/out question in addition.