Lip skin is extremely thin and contains almost no melanin – the body’s natural sunscreen. As a result, lips don’t tan, but they can easily burn. Even if you don’t notice your lips being burnt by the sun, damage can still occur, with the underlying layers being harmed.

It’s not just on hot, sunny days that lips must be protected – the harmful UVA rays remain at constant levels throughout the year, including the winter months. Even on cloudy days harmful UVB rays can still penetrate and damage skin.

The snow can be even worse for lips than the sun. Whereas sand and water at the beach reflects less than 20 per cent of the sun’s rays, snow reflects a punishing 80 per cent - and the higher up the slopes you go, the less air there is to screen the sun’s rays.