Media playback is unsupported on your device Media caption David Cameron: '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.'

David Cameron has given his clearest hint yet that he will back a referendum on Britain's relationship with the EU if the Tories win the next election.

He said there will be opportunities for the British people to give "fresh consent" to the UK's EU membership.

Closer economic ties between eurozone countries "will give us opportunities for changing our relationship with Europe", he said.

However, he added he thought it was not in Britain's interest to leave the EU.

The prime minister has faced calls to back an in/out referendum from his own MPs, 81 of whom rebelled against the party line last year to vote for a referendum.

Some Conservative MPs fear the UK Independence Party - which has long campaigned for the UK to leave the EU and for the public to have their say in a referendum - could lose the party seats at the next general election if Mr Cameron does not take a more Eurosceptic stance.

'Revealing response'

Speaking during a trade visit to Brazil, Mr Cameron told the BBC: "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.

Analysis That multisyllabic R word, referendum, didn't tumble out of David Cameron's mouth. But there was a hint, a nod, a wink, a smile in that direction. "A new settlement" that would "require fresh consent" the form of words he chose. The pitch is this: the changing political and economic geography of Europe will change the very club, the EU, which the UK is currently a member of. That, Mr Cameron says, offers the chance for something of a renegotiation. It is difficult to paper over the differences between an instinctively Eurosceptic Conservative Party and the instinctively pro-European Liberal Democrats. With just a week to go until the Conservative Party conference, David Cameron will be aware, a year on from 81 of his MPs rebelling over Europe, that Euroscepticism hasn't melted away. Some blame what they see as his flaky approach to the subject costing the party a majority at the last election. They fear a lack of clarity next time could lead to exactly the same outcome.

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

Stewart Jackson, who resigned as a ministerial aide over Europe, cautiously welcomed Mr Cameron's comments.

Mr Jackson told the BBC: "I am pleased because ultimately this is an opportunity for him to show great leadership."

"UKIP could cost us an overall majority at the next election, so this is moving in the right direction."

But he added: "Only a straight in/out referendum will wash with the voters."

'Step forward'

Tory MP John Baron, who delivered a letter to Downing Street in June, co-signed by 100 Conservative MPs, calling for an EU referendum said he had now received a "revealing" response from the prime minister.

Mr Baron said: "In the past, the PM has agreed that the objective is to have less Europe, and has not ruled out a referendum.

"However, this letter talks of getting the fresh consent of the British people once a fresh deal becomes clear following concerted efforts to change the status quo. It is a step forward."

However, the prime minister did back Mr Baron's call for a legal commitment now to hold a referendum after the next election.

"There are many upsides in committing to a referendum now - not least it would address the very real lack of public trust when people hear politicians making promises about the EU," said the Tory MP.

"We will continue to press the prime minister on this point."

Mr Baron is setting up a cross-party group to campaign on the issue, which will meet for the first time on 16 October. Membership of the new group was, he said, "going great guns".