The National Institute for Health and Care Excellence (NICE) has issued guidance warning that there is no safe limit of exposure to the sun. The guidance comes against a background of dramatic increases in the number of hospital admissions for skin cancers in recent years, particularly for malignant melanomas. The cost to the NHS is estimated at around £100 million. 

Experts have long urged people to take greater responsibility for protecting their skin from the harmful UV rays in direct sunlight. NICE recommends that adults should apply sun cream 30 minutes before going out in the sun and then again just before. They need to use around 35ml and the cream should have a protection factor of 15 or higher. The guidance warns that a higher factor lotion does not necessarily mean people can spend more time in the sun without the risk of burning. They also need to reapply sun cream if their skin becomes wet or the lotion is rubbed off. 

Some groups, including babies and children, those with fair skin or hair, and people with a lot of moles or freckles, are at higher risk. People who work outside are also urged to take particular care. Having an existing tan provides very little protection. 

People also need to be more aware of the signs and symptoms and to seek medical treatment early. Melanomas often appear larger and more irregular in shape than moles. They can be different shades and colours and are sometimes itchy or bleed.

The guidance acknowledges that some exposure to sunlight is needed to build up levels of vitamin D but this has to be balanced against the risk of skin cancer. In the UK, low light levels between October and March make it impossible to get enough vitamin D but the guidance does not set out any safe or maximum level of exposure. 

Andrew Clayton of Penningtons Manches' clinical negligence team says: "Although there has been increased publicity of the risks of over-exposure to the sun in recent years, cases of skin cancer are still rising. The difficulty is that there are still no hard and fast rules about what is safe. Inevitably, this depends on environmental and personal factors. Location, time of year, the weather and a person's age and skin tone all play a part and are variable, so a degree of common sense is needed.  

"Early diagnosis and treatment are key to a positive outcome in cancer cases but, with the NHS’ stretched resources, we encourage everyone to do more to avoid the risk of skin cancer in the first place."