British viagra men may be enjoying a 'summer penis' thanks to warmer weather but doctors warn that as the mercury rises so too does risk of erectile dysfunction.

Summer penis is a term given to the phenomenon where men find their manhood swells in size as the temperature climbs.

This is a simple biological reaction to the heat with blood vessels in the member expanding instinctively to help cool the body.

As a result, this can make the penis seem slightly larger or fuller than normal.

However, Dr Donald Grant, a GP and senor clinical advisor at The Independent Pharmacy, warned that warmer weather wasn't completely good news for men's nether regions.

'Across the UK, we've been blessed with some incredible spring weather as temperatures exceed 25C in some cities,' he said. 

'While this is welcome news, the warm weather can also affect many health conditions, exacerbating symptoms. This includes erectile dysfunction (ED).