A recent UK scientific study on the efficacy of sun creams says that although they help prevent sunburn, lotions fail to block out the harmful ultraviolet rays which can cause the skin cancer. Sun block could give sun worshippers a false sense of security.

Burns specialist Professor Roy Sanders said that the only way to really protect the skin is to stay in the shade at the hottest times of the day or cover up with hats and T-shirts.

According to Professor Sanders, one in 68 of the present UK adult population will be diagnosed with malignant melanoma – the most dangerous form of skin cancer – at some point in their life. By 2010, however, that figure will have risen to one in 50.

Skin cancer can be caused by two types of ultraviolet light, the short, energetic wavelengths of light in the sun’s rays. UVA penetrates the skin most deeply and can suppress the immune system and damage cells. UVB also damages skin cells. The ‘factor’ rating on a bottle of sun block refers to the level of protection against UVB, historically considered the greater danger. A little-known one to four star system – normally printed on the back of bottles – indicates the level of protection against UVA.