When it comes to l'amour, the French are speedy lovers

The study of 14 countries says that while 42% of Britons admit to having more than one relationship at a time, half of all Americans are having affairs.

In the rest of Europe, two-timing Italians account for 38% of their population, unfaithful French for 36% - and straying Spaniards for 22%.

Durex brand manager Debbie Zadeh said of the British findings: "This is surprisingly high, as the British have never really looked on themselves as being the adulterers of Europe.

"The results from the survey are bound to make everyone a little more cautious about their own partner, and of course underline the importance of always practising safer sex."

The survey of sexual attitudes showed that the French are ahead of the field in their frequency of love making.

While Americans do the deed 138 times a year, the French achieve a grand total of 141 sexual encounters per annum.

One in five British men would make love to a stranger - if she asked nicely

Brits chalk up 112 liaisons over the same period.

But if Americans are pipped at the post for frequency, they make up for it with stamina, taking an average of 28 minutes to have sex.

Australians come a close second at 23 minutes while Brits manage to endure just under 23 minutes.

Even though Paris was voted the most romantic place in the world by men and women of all ages, French citizens were found to take just 16 minutes over love making - leaving more time to take in the sights of the capital city.

Lovers in Thailand are fastest of all, devoting 10 minutes to the task.

Just 138 times?

The survey, which involved face-to-face interviews with more than 10,000 sexually active adults, found that British men and women are having sex at an increasingly earlier age - but Americans are waiting longer for their first encounter.

On average, British people are 16.7-years-old when they lose their virginity, compared to 17-years-old a year ago.

However, the earth doesn't always move first time, with more than four out of ten of all people surveyed remembered their initiation as "disappointing".

Give it away for free

Germans had the worst first time, with 49% finding the experience unsatisfactory, followed by the Russians, where 47% said they were less than fulfilled.

And when cash came into the equation, the study found that British women would not be opposed to an indecent proposal - if the price was right.

More than 80% of women said they would make love to a stranger for a £1m, but only six per cent would do it just because he was good looking.

Thailand: Home to the fastest lovers in the world

British men, on the other hand, claimed the moral high ground, with only 68% ready to sell their body to £1m bidders.

Yet one in five said they would give it away for free to any beautiful woman who asked.

And when all countries - America, Australia, Britain, Canada, France, Germany, Hong Kong, Italy, Mexico, Poland, Russia, South Africa, Spain and Thailand - were asked which nation made the greatest lovers, the survey showed:

• France - 58%

• Italy - 45%

• America - 36%

• Britain - 18%

• Germany - 15%

• Poland - 8%