Forget the pictures you've seen in adult films and the "lifelike" drawings scrawled on public bathrooms, there is now a scientific guide for the average penis size - and hopefully it will put some men at ease.

British researchers have pooled the measurements of more than 15,000 men's penises to more closely determine what constitutes "normal-sized" anatomy.

They found the average penis is 13.12 centimetres when erect and 9.31 centimetres when flaccid.

The team, led by psychiatrist David Veale, created graphs of both length and girth, finding the vast majority of men range between 11 and 15 centimetre in length and between 10 and 13 centimetres in circumference when erect.

"We believe these graphs will help doctors reassure the large majority of men that the size of their penis is in the normal range," said Dr Veale, a specialist in body dysmorphic disorders at King's College London Medical School.