Scientists believe drinking too much alcohol could set off a chain of reactions in the body that makes the skin more vulnerable to cancer.

Ethanol is converted to acetaldehyde soon after ingestion and this compound may render the skin more sensitive to harmful UV light, they say.

The authors of the work in the British Journal of Dermatology admit that other forces may also be to blame.

Drinkers may lounge in the sun without enough protective clothing or suncream.

According to their work, which looked at 16 different studies involving thousands of participants, consuming an alcoholic drink or more a day increases skin cancer risk by a fifth.

Risk increased proportionately with alcohol intake - those who drank 50g of ethanol daily (the equivalent of a few strong beers) were up to 55% more likely to develop the deadliest form of skin cancer called melanoma compared with non or occasional drinkers.

Dr Eva Negri, one of the study authors who is from the University of Milan, said: "We know that in the presence of UV radiation, drinking alcohol can alter the body's immunocompetence, the ability to produce a normal immune response.

"This can lead to far greater cellular damage and subsequently cause skin cancers to form. This study aimed to quantify the extent to which the melanoma risk is increased with alcohol intake, and we hope that armed with this knowledge people can better protect themselves in the sun."

Prof Chris Bunker, President of the British Association of Dermatologists, said: "Skin cancer is the most common type of cancer in the UK and melanoma is its deadliest form. Any research into this area is very welcome.

"Brits haven't always been known for their moderation when it comes to either alcohol or the sun, but this research is important as it provides people with further information to make informed choices about their health.

"We would always urge people to be careful in the sun and try to enjoy it responsibly. It is not uncommon to have a few drinks whilst on holiday or at a barbeque, we would just encourage people to be careful and make sure they are protecting their skin, this research provides an extra incentive to do so. Many of us have seen holiday-makers who have been caught unawares the day before, fuzzy-headed and lobster red - an unwelcome combination."

Sarah Williams of Cancer Research UK, said: "This study doesn't tell us for sure whether alcohol is a risk factor for melanoma. As the researchers themselves point out, the results could be due to sunlight exposure rather than alcohol. Research has clearly shown that most cases of melanoma are caused by overexposure to UV rays - you can reduce the risk by avoiding sunburn."

She said that in winter, the UK sun isn't normally strong enough to cause sunburn, but added: "Remember to protect yourself if you're skiing or going away for some winter sun."

"And whether or not alcohol is linked to skin cancers, it's still a good idea to limit the amount you drink. Alcohol is linked to seven different types of cancer, and cutting down can cut the risk."