The Department of Health-funded report says "in general, Britain is a happy nation" with 70 per cent of those questioned expecting more positive than negative experiences.

The report, 'Some Are More Equal Than Others' by the National Social Marketing Centre and University College London, found that high earners -with a salary above £30,000 a year - were the happiest with a 80 per cent rate of optimism.

The survey, which questioned 1,994 people, was carried out in August during Britain's successful run at the Olympics.

However the report has been published at a time of greateconomic uncertainty.

Economists have forecast a recession and academics admit that rising unemployment numbers and financial worries could affect people's mood.

"These sorts of surveys tend to stay fairly stable... but in August [the economic outlook] was less bad than it is now."

"In a sense you need to have optimism for your mental health," he said.