A SIMPLE pill which could stop people developing skin cancer by repairing sunburn damage has moved a step closer.

Researchers have found out how animals protect themselves from the sun’s harmful rays.

And the groundbreaking discovery will now pave the way for the creation of a drug or ointment that ends the scourge of summer holiday sunburn – and protect against one of the most deadly cancers.

Skin cancer is the most common form of the disease in Britain with rates rising faster than any other cancer type. The timebomb is exploding three decades after sunny holidays abroad became popular, with more than 100,000 cases diagnosed each year.

But after 10 years of research, experts have made the breakthrough in how the effects of too much sun can be reversed. When humans get sunburn the majority of our skin cells can repair themselves but the damage to DNA often leads to cells being killed off. Over time, the unrepaired area can develop into skin cancer.

Experts have long known that humans lack a key enzyme, which is present in insects, fish and marsupials, which appears to repair the damage done to DNA by exposure to sun.

Now scientists in America have pieced together how the enzyme, called photolyase, works to repair DNA. The findings of Professor Dongping Zhong and his team in the physics department at Ohio State University, contradict accepted theories of how key DNA molecules break up during the repair of sunburn.

Harmful ultraviolet light causes molecular injury to DNA and prevents it from replicating properly.

But for animals which produce photolyase, the enzyme absorbs energy from visible light to shoot an electron into the damaged area.

This instantly heals the damage, resulting in a perfectly repaired strand of DNA.

Dr Zhong said: “People have been working on this for years, but now that we’ve seen it, I don’t think anyone could have guessed exactly what was happening.”

The scientists published their results in the Proceedings of the National Academy of Sciences and hope that others will use the knowledge to create synthetic photolyase for drugs or even lotions that can repair DNA.

Normal sunscreen lotions work by converting UV light to heat, or reflect it away from our skin.

A sunscreen containing photolyase could potentially heal some of the damage from UV rays that get through. Dr Safia Ali Danovi, Cancer Research UK’s senior science information officer, said: “Ultra-violet causes DNA damage, which can lead to skin cancer.

“But there’s no quick fix for the harm caused by sunburn. And with skin cancer rates rising, it’s important that people enjoy the sun safely.”

Malignant melanoma, the most dangerous skin cancer, kills around 2,000 people a year in Britain – more than in sunny Australia.

About 10,000 new cases are recorded annually, with rates quadrupling in the past 30 years.

It is estimated that around 80 per cent of melanomas are in fair-skinned people, and 90 per cent of non-melanoma skin cancers are caused by sun exposure.

Risk of melanoma is most strongly linked to intermittent exposure to high-intensity sunlight, often resulting in sunburn, rather than to exposure typical of that received by people with outdoor occupations.

However, a history of sunburn doubles the risk of melanoma.

But a certain amount of exposure to the sun is healthy – we need 15-20 minutes per day to get our recommended dose of Vitamin D.