This tends to mean that two commonly used chemical UV filters linked to coral bleaching – oxybenzone and octinoxate – aren’t used. Mineral sunscreens in particular often promote their environmental credentials, the most common being that they’re ‘reef-safe’ or 'ocean-friendly'. Calypso Once A Day may cause staining on certain fabrics and surfaces. Always cover seats and cushions. May discolour nail products. Some people worry that using sun cream might prevent them from getting enough vitamin D, but this isn’t the case unless you really overdo it. If you're using sun cream at the beach, apply plenty before swimming, and again when you leave the water. Reef-safe sun creams

Unwanted Food or Drink Products - Once supply conditions are broken, there are a number of factors outside of our control that can affect the quality of a product. Therefore perishable goods such as food and drink cannot be returned. Since our 2016 investigation, the CTPA has advised brands to voluntarily stop making 'once a day' claims and move towards using the word 'durable' instead. What's more, even if you follow all the rules, it's possible you won't get as much as protection as you expect. Even with our test subjects just sitting on a chair in a T-shirt, we saw substantial reductions in the level of sun protection, so we don't think you can rely on once-a-day sun cream to keep you protected all day. It takes longer for those with darker skin that rarely burns – it can take 25-40 minutes for the darkest skin type.The British Association of Dermatologists (BAD) says frequent reapplication of sun cream is important, regardless of how long any product claims to give protection for. It is essential to buy a sunscreen that has a high SPF. You should also do some research online to see which sunscreens have undergone independent tests by credible third parties. Our Press and ProtectSPF30 Sun Lotion was chosen as the Which? “Best Buy Sunscreen” for two years in a row. Our other sun care productscome recommended by The Independent and The Telegraph.

For more details on the importance of vitamin D and where to buy supplements, see our in-depth vitamin D guide . Other ways to stay safe in the sun When choosing sun cream for your child, look for a short ingredients list and the terms 'fragrance free' and 'hypoallergenic'. The WHO recommends 35ml of sun cream (seven teaspoons' worth) to cover an adult, so use around a quarter to a half of this depending on the size of your child. Mineral sunscreens fail Which? SPF and UVA tests - find out what happened when we put pricey mineral formulations to the test in our independent labAvoid sun exposure between 11am - 3pm. Seek shade and always protect children with a hat, loose clothing and high SPF protection.