The average British man or woman has slept with 2.8 million people - albeit indirectly, according to a report by news agency AFP.

A British pharmacy chain has launched an online calculator which helps you work out how many partners you have had, in the sense of exposure to risk of sexually transmitted diseases (STIs).

The "Sex Degrees of Separation" ready reckoner tots up the numbers based on your number of partners, then their previous partners, and their former lovers, and so on for six "generations" of partners.

The average British man claims to have actually slept with nine people, while women put the figure at 6.3, giving an average of 7.65.

"When we sleep with someone, we are, in effect, not only sleeping with them, but also their previous partners and their partners' previous partners, and so on," said Clare Kerr, head of sexual health at Lloydspharmacy, AFP reported.

"It's important that people understand how exposed they are to STIs and take appropriate precautions including using condoms and getting themselves checked out where appropriate."