DAVID Cameron has given his most optimistic assessment yet of the British economy, saying there are now "good signs" that growth is strengthening.

Following the success of the London Olympics, the Prime Minister said the "British brand" had never been stronger overseas.

During his trade mission to Brazil, which has seen £100 million agreed in deals, Mr Cameron struck an upbeat note about the UK's economic prospects.

"In the last two years we've seen a million net new jobs in the private sector. That shows our economy is rebalancing. For too many years, the state was too big and the private sector was too small," he said. "Businesses are starting up in Britain at a record rate. We need to get behind that and encourage that."

Asked if he thought the economy had now turned the corner, the PM replied: "I'm not a forecaster; it's not for me to say that. But what is happening is the rebalancing I'm talking about; that's happening. The private sector is growing the number of jobs, the number of people employed. Last year a record number of businesses were created in Britain."

His comments follow remarks by one of his predecessors, Sir John Major, who claimed Britain had passed the darkest point in the economic crisis.

In a separate development, Mr Cameron gave his strongest signal he is ready to support a referendum on Britain's relationship with Europe after the next General Election.

The Prime Minister said Britons would have to give "fresh consent" to the UK's membership of the European Union as eurozone nations integrate closer.

l Boris Johnson has accused Mr Cameron of pretending not to know what Magna Carta means so he did not appear too clever.

However, in a blow to his own carefully crafted man-of-the-people image, the London Mayor did not know who scored a hat-trick for England in the 1966 World Cup final.

Mr Johnson's claim the Tory leader feigned ignorance exposes the growing rift between the pair.