According to research by experts at the University of Oslo, the University of Bergen and Harvard Medical School, the middle-aged man showed similar levels of contentment to those who were physiologically in their sexual prime, aged between 20 and 29.

Sexual contentment hits the average 50-year-old in spite of increased problems with sexual functions such as attaining, and sustaining, an erection, the study said.

Researchers in the US and Norway spoke to 1,185 men aged between 20 and 79.

Professor Sophie Fossa who helped conduct the research published in BJU International, the British journal of urology, said men in their middle years were found to be far more satisfied with their sex lives than those in their 30s and 40s.

Men were asked to rate "sexual satisfaction" from zero to four, with four representing the greatest degree of contentment.

Men in their 50s recorded an average satisfaction level of 2.77, second only to their 20-something counterparts, who recorded a marginally higher average result of 2.79.

Men in their 30s reached 2.55, while men in their 40s were at 2.72.

But the survey found that as men hit the end of their 50s, overall sexual satisfaction levels tended to plummet to 2.46 for men in their 60s and 2.14 for men in their 70s.