Sunbeds have been promoted in the past as a healthy alternative to frying on the beach. While natural sunlight delivers a combination of UVA and UVB ultraviolet radiation, which stimulates skin cells to produce the brown pigment menalin, sunbeds screen out the more potent UVB, known to cause skin damage and cancer.
For many years doctors believed UVA was safe, but the discovery that psoriasis patients treated with UVA radiation were developing skin cancer prompted more research - and some disturbing results. Like UVB, UVA radiation has been found to damage chromosomes in the skin cells, increasing the chance of a cancer developing; in the case of UVA, those cancers are more likely to be manifest in the most serious form, malignant melanoma. This year more than 40,000 people in the UK will get skin cancer, 10 per cent of them melanoma.
But UVA does not just put your health at risk. By penetrating more deeply, it damages the elastin and collagen that keep skin firm and supple, causing premature ageing in the form of lines, wrinkles and sagging. Those using sunbeds for more than 20 sessions a year also run the risk of developing skin fragility, a condition normally confined to the elderly, where the skin becomes very thin and transparent, and bruises and blisters easily.
According to recent research by the Imperial Cancer Research Fund, sunbeds give out two to three more times more UVA than sunlight: an average 30- minute session contains the equivalent UVA dose as a day at the beach. The charity believes there is no safe level of use, with some people naturally more at risk than others. You should not use sunbeds, for instance, if you are under 16, have fair skin or have a family history of skin cancer, are taking drugs which make your skin sensitive to light, or have a large number of moles or freckles.
And it is no use consoling yourself with the thought that a light tan from a sunbed will prepare your skin for the ultraviolet onslaught of a couple of weeks in Benidorm. A tan offers little protection from the sun - at best, it is equivalent to a sun cream with protection factor 2-4. As UVA does not produce the thickening of the outer layer of skin which helps to protect against burning, tans from sunbeds are even less effective.
Despite growing evidence that all tanning is damaging to some degree, a study by the Office for National Statistics recently found 49 per cent of women and 40 per cent of men still believe that having a tan makes them feel healthier and look more attractive. If you are one of those who really cannot face the thought of life beyond the bronze age, Dr Veronique Bataille, consultant dermatologist at the ICRF's Skin Tumour Laboratory, suggests you stick to sunlight.
Even taking into account the increased exposure caused by the thinning of the ozone layer, the sun offers a more natural spectrum of radiation and, by producing redness and burning, the UVB component acts as an alarm signal to cover up. The trouble with sunbeds is that you can have a much higher dose without realising it.
Altogether a safer alternative is to use chemical suntan creams, which dye the superficial layers of the skin with a brown pigment. Better still, use sunblock on exposed areas and resign yourself to looking pale and interesting. Twenty years from now you will be reaping the benefitsn