It's clear that there are plenty of conditions to fulfil to get the claimed protection from once-a-day products, which may be hard to achieve if you're on a day out in the sun. Apply evenly and generously to all exposed areas 15 minutes before sun exposure, then rub in well to allow the product to bind with the skin and form a protective film against UVA and UVB rays. SPF stands for Sun Protection Factor and represents the sunscreen’s ability to protect your skin from the sun’s rays in addition to your skin’s natural protection. Depending on your skin type, hair colour, eye colour and location, you may be able to stay in the sun for 10 minutes without burning. A spokesperson added: 'As with all sunscreens, it is important to follow the instructions for application and use; and sunscreen should not be used to intentionally stay longer in the sun. Sunscreen is just one part of a sun safe regime.' Boots We made multiple attempts to get in touch with Calypso, but the brand did not respond to any of our questions or send us a comment. Riemann

A spokesperson told us that all of its sun creams are designed for 'longevity' but that it found the use of the word 'durable' more 'appropriate' than once a day. We agree that the claim “Once a day” can be anticipated in a wrong way by the consumer, and it is one of the reasons why we changed our durability communication from “Once a day” to “Up to 10 hours”.A spokesperson said: 'Soltan Once products clearly state how they should be used and when to reapply. We are confident in the claims for the Soltan Once range and refute the suggestion that they are misleading. Important: Read the instructions carefully before use. Apply to clean dry skin, preferably after a shower. Apply evenly and generously 15 minutes before exposure to the sun, which will allow the product to bind with the skin and form a protective film against UVA/UVB rays. When used correctly, one application is sufficient for all day protection.

But do 'once a day' sunscreens really last all day? And should you rely on them? Our research, and the small print on the bottle, suggests you may need to re-apply more often than you think. Our Once a Day Sun Protection only needs to be applied to the skin once and protects you all day long. The water resistant formula provides protection against both UVA and UVB rays. The range consists of five products ranging from SPF10 to SPF50+ and we recommend our Once a Day SPF40for kids as it is suitable for their delicate skin. I had difficulty getting hold of my usual day-long sun cream so took a chance on this. . As others have said, it’s a gel and not a cream, but it absorbs super fast and it’s easy to apply. 2 weeks in day-long sunshine over 30 degrees and I have a good tan and no sunburn. I also usually suffer from heat rash but not with this product. The Calypso Once A Day range offers effective, highly water resistant sun care products that provide UVA/UVB protection. Constantly re-applying sun cream when you're out and about can be a real chore, especially if you're trying to keep wriggly kids protected.

Reapply sunscreen after swimming, sweating heavily, towel drying, or rubbing your skin in a way that might cause the cream to rub off. So it's not surprising that brands have sought to make life easier for us by developing hard wearing sun creams.

We're pleased to say that we don't test any of our products on animals. What's more, we don't buy ingredients that have been tested on animals by another manufacturer. So you can buy Calypso confident in the knowledge that your sun care is cruelty-free.Formula conforms to European recommendation for protection against the harmful effects of UVA and UVB rays.

Don't just rely on sunscreen either: use clothing, hats, sunglasses to cover up, and seek shade, particularly when the sun is strongest, between 11am and 3pm - regardless of whether you are wearing sun cream. Professor Brian Diffey recommends applying sun cream like you would paint to a wall - you'd rarely just do one coat. Two coats of paint are almost always required for satisfactory coverage. In the same way two coats of sunscreen may be required for adequate protection,' he said. Once a Day SPF40 Sun Protection (150ml) is water resistant so only one application is needed for the whole day. The formula provides protection from the sun’s damaging rays and is specially enhanced and designed to protect children’s delicate skin. So, if you are only applying your sunscreen once a day, you are at risk of spending hours in the sun with little or no protection to those areas of skin that may have been missed.' Do not exceed exposure to the sun for longer than your skin type allows, taking into account the strength of the sun.Unlike traditional sunscreens that require re-application on a regular basis, Calypso Once A Day can be applied only once and will protect your skin from harmful sun radiation. The only bad thing is it smells quite strong, like ammonia. So avoid your eyes! My first day I rubbed it all over my face and my eyes watered all day but from then I just avoided my eye area and it was great. Some regular sun creams also make my eyes water.