And finally…money can by happiness - but even millionaires say they need more

The Ivy League researchers quizzed 2,000 millionaires for the study, which is considered to be the first of its kind.

Michael Norton, a professor at Harvard Business School was given access to his respondents through an investment bank that put him in touch with some of its wealthiest clients.

He asked them how happy they were on a scale of one to ten and how much more money they would need to reach ten on that scale.

“Basically everyone says [they’d need] two or three times as much,” Professor Norton told The Atlantic magazine.

The study found that around a quarter of millionaires with a net worth of more than $1.5 million (£1.18 million) said that they would need 1,000 per cent, or about eleven times, more money to be perfectly happy, while another quarter said they would need six times as much wealth and another quarter said they would need twice as much.

This pattern “did not differ by wealth” and the belief that they would need a lot more money to achieve perfect happiness was expressed even by those with a net worth of more than £7.5 million.

Millionaires with wealth of more than £6 million were found to be happier than those with about £1 million but this extra wealth leads only to “modestly greater well-being”, the study said.

However, those who earned their fortune were happier than those who merely inherited it, suggesting that accomplishing goals is key to satisfaction.

The full results of the study were published in Personality and Social Psychology Bulletin.