Britain is shrugging off its prudish image after a study found its citizens to be the most promiscuous of any large western industrial nation, while Australians ranked fifth.

An international index measuring one-night stands, total numbers of partners and attitudes to casual sex also put Britain ahead of second-placed Germany, with the Netherlands third, the Czech Republic fourth and the US sixth.

Researchers behind the study say high scores such as Britain's may be linked to society's increasing willingness to accept sexual promiscuity among women as well as men.