This is pretty scary.  One of the handiest ways to protect yourself from the sun is to wear the once-a-day suncreams, which only requires one application for the whole day. They promote prolonged sun coverage throughout they day. However, experts at Which? have conducted some tests on these suncreams and the results are alarming. They conducted controlled tests where participants applied the suncream to their backs and then spent the day in the lab. During this time, they wore a t-shirt and were allowed to sit on a chair. After six to eight hours, depending on how long the product claimed to last, they retested the sun cream’s SPF. While they pointed out that they didn't test subjects for heat or water reduction, they said that a lot of holiday goers would spend time on sun loungers or on a towel or simply wearing a T-shirt, so they focused on these activities for the test. After testing out the products, they saw an average 74% decrease in SPF protection. They reckon the main reason for this reduction were the volunteer’s back rubbing against their t-shirt and the chair. Cancer Research UK says, ‘The amount of protection you get depends on how well you put it on. It’s easy to miss bits when you’re applying suncream. CRUK recommends you reapply regularly to help get even coverage of your skin." Furthermore, once-a-day suncreams are banned in Australia as they have much stricter rules when it comes to sun protection that in the UK. Included in the tests were, Boots Soltan Once 8hr Sun Protection SPF30 (200ml), Piz Buin 1 Day Long Lotion SPF30 (150ml), Riemann P20 Once a Day Sun Protection SPF30 Spray (200ml) and UltraSun Family SPF30 (100ml).