Millions of people are risking their lives by not applying sunscreen properly, warn skin cancer specialists.
After a scorcher yesterday, and with much of the country on track for a repeat today, a shock new survey revealed eight out of ten Brits don't apply protection before going out in the sunshine.
The poll of 215 people, conducted online by the British Association of Dermatologists to mark Sun Awareness Week, also found that 70 per cent of people fail to reapply sunscreen every two hours as recommended.
Skin cancer experts recommend applying sunscreen before going outside in sunny weather for three key reasons: to make sure that the product is fully absorbed before skin is exposed to the sun; to help reduce the chances of areas of skin being missed, and to ensure a thick enough layer is applied.
They say confusion over how, or when, to apply sunscreen may explain the findings of a previous survey by the Association that 72 per cent of people admitted they'd been sunburned in the previous year.
The new research also found that more than a third (35 per cent) would only seek shade if they were hot, rather than to avoid burning.
Of all forms of protective clothing, sunglasses were by far the most popular, worn by 81 per cent of people, suggesting that people are more concerned with protecting their eyes than their skin, or just wear them to be fashionable.
Doctors say the findings are of grave concern given that the risk of developing melanoma - the deadliest form of skin cancer - more than doubles in people with a history of sunburn compared with people who have never been sunburned.
Skin cancer is the most common cancer in the UK and rates have been climbing since the 1960s. Every year more than 250,000 new cases of non-melanoma skin cancer - the most common type - are diagnosed, in addition to more than 13,000 new cases of melanoma, resulting in around 2,148 deaths annually.
Johnathon Major, of the British Association of Dermatologists, said: "Sunscreens are an important part of good sun safety practices, though they must be applied properly for them to be effective.
"Applying liberally half an hour before going out into the sun, and then again shortly after going outside, is vital to ensure that you are fully covered and that the sunscreen has had time to be absorbed into the skin.
"It should then be reapplied at least every two hours, as the protective filters can break down over time. It should also be reapplied after any activity where it might be accidentally removed, such as swimming.
"Water-resistant sunscreens are not friction-resistant, and therefore they can be accidentally removed if you towel dry after swimming or sweating.
"These results show just how widely sunscreens are not being used properly by the British public, and highlight an important area for sun awareness campaigns to target.
"While we have succeeded in making people aware of the link between sunburn and skin cancer, we have more work to do in teaching people how to use sunscreen properly.
"Education is key if we are going improve sun safety habits and prevent the public from putting themselves at risk."
Stevie Cameron, of sun protection brand La Roche-Posay which is sponsoring the awareness campaign, said: "It's really important that the British public are using the right sunscreen.
"When choosing a sunscreen, it is important to look for a high SPF value, such as 30 or 50+ that protects against UVB rays.
"In addition, it is very important to look for a circled UVA logo. This means the sunscreen meets EU requirements for UVA protection, rays that are present all year-round.
"Today the best sunscreens provide protection against UVB and UVA rays.
"As for those who do not 'get on' with the texture of normal sunscreens - there are textures on the market that are specifically formulated for sensitive, dry or oily and blemish prone skin."