We’ve all seen them. On the beach, in the park or at the pool, there’s always someone aiming for that must-have fashion accessory, the suntan. But, as they lie there slowly roasting, they might be giving themselves more than just a peeling back or chest. It is an ironic consequence of our image-obsessed society that, as more and more of us pursue a bronzed look, skin cancer has become the fastest growing form of the disease.

A tan, whether acquired at the beach, around a pool or on a sunbed, might be seen as healthy and trendy, but pale-skinned people are putting themselves at risk by trying to achieve a Mediterranean-style complexion through binge sunbathing. Changes in our diet and lifestyle are driving down the incidence of some forms of cancer. But the number of new skin cancer cases has doubled over the past 15 years. More than 5,000 cases of melanoma are identified each year in the UK, and around 1,500 of these will end in death. But nearly all skin cancer deaths are preventable because, with early diagnosis, most can be successfully treated.

Melanoma is the least common of the three main types of skin cancer, but by far the most serious. The first sign is usually a mole starting to change colour, size or shape. If caught in time, these early or “thin” melanomas have a five-year survival rate of 95 per cent, but more advanced tumours can quickly spread to other parts of the body.

Each year, around 40,000 people develop the less dangerous basal cell carcinoma and squamous cell carcinoma. Although these are almost always curable, in 1998, 467 people died from non-melanoma skin cancers (NMSC). Basal cell carcinomas, sometimes known as rodent ulcers, usually appear on the face as flesh-coloured lumps, while squamous cell carcinomas, which occur on parts of the body that get a lot of sun such as the face, hands, back and legs, have a hard, scaly surface and may bleed when touched. If you include NMSCs in the statistics - and they are routinely omitted these days because they are so common and less serious than melanoma - skin cancer is the most prevalent form of the disease in the UK today.

Over-exposure to sun in childhood is known to increase the risk of developing skin cancers in later life - and continuing to sunbathe as you get older can trigger a melanoma. Those particularly at risk are office workers who jet off for a fortnight in the sun and submit their pasty skin to an intensive blast of UV rays.

Daffyd Roberts, chair of the Skin Cancer Working Party, a confederation of dermatologists and cancer specialists that aims to co-ordinate health education, admits they have a difficult job. “It’s frustrating,” he says. “We have lots of evidence from studies that show we have succeeded in increasing people’s knowledge about skin cancer. The problem is that their behaviour doesn’t change that much - young people in particular. Even though they know the sun can cause skin cancer, they think it won’t happen to them or it will happen at some far-off date.”

As with teenage smoking, it may be a long time before the health message can overcome peer pressure and the desire to “look cool”, he says. But there are signs that the message is getting through to some groups - the rate of increase of melanoma among women has levelled out and mortality is stable. “That’s good news,” says Mr Roberts, “but then women always listen to health messages. The group that doesn’t listen is men. As a rule, they are very poor at looking after their own health.”

Our curious and sometimes contrary attitude to suntans was shown in a recent survey by the Imperial Cancer Research Fund. More than 70 per cent of those interviewed said they wanted a tan - even though 55 per cent of the same group thought people with one were vain and overly concerned with their appearance. Seventy-one per cent thought a tan looked healthy, but almost as many (68 per cent) acknowledged that getting one can mean damaging one’s skin or health. The safest type of tan - a fake one - was preferred by just 4 per cent.

But attitudes can change. In Australia, the harsh sun, combined with the popularity of beach culture - and the fact that most locals are descended from fair-skinned immigrants - caused alarming rates of skin cancer. But after the “Slip, Slop, Slap” campaign (slip on a shirt, slop on some sun cream and slap on a hat) was introduced in the 1980s, rates dropped by 11 per cent among 14 to 50-year-olds.

Former teacher Robert Jinks knew all about the risks, the precautions and the tell-tale signs. It was lucky he did, because two-and-a-half years ago, at the age of 42, he noticed a small, white lump between his eye and his nose. “It just came up - I could almost see the thing growing,” he remembers. He went to his GP, who told him it was harmless and not to worry. But Mr Jinks, who was a maths and PE teacher before he started work as a fundraiser for the Cancer Research Campaign eight years ago, couldn’t stop worrying. He went back to his doctor who removed the pea-sized lump under local anaesthetic and sent it off for analysis, which confirmed it as a basal cell carcinoma. “I was shit-scared,” he confesses. “It literally smacked me in the face.”

The cancer was growing into his face and had to be removed before it threatened his eyesight, so he had another operation to take out the surrounding skin cells and plastic surgery to repair the damage. He avoided chemotherapy and now the only sign that he ever had cancer is a small scar, which you can see only when he takes off his glasses. Fair-skinned and balding, he wasn’t a sun-worshipper as an adult, but he remembers getting burned on childhood holidays. As he sees it now, he is “paying the penalty of my parents’ ignorance”. As with many people of their generation, their idea of sun protection was to apply some calamine lotion to his blistered skin.

“Having cancer has made me even more aware of the risks, and intent on making other people aware,” says Mr Jinks, who now gives talks to children in schools warning them of the dangers of excessive sunbathing. “I would urge anyone who is going abroad to cover up, be sensible in the sun, wear high factor creams, and if they have anything like a mole or a lump that they are not sure about, get it checked out.”

THE PERILS OF SUN SPOTS

Cases of malignant melanoma have doubled in the past 20 years to more than 5,260 in 1998 - when there were 1,640 deaths. Skin cancer affects a disproportionately large number of young people. Among 20 to 34-year-olds, it is the third most common cancer in women and the fourth most common in men.

Although exposure to the sun is known to be the major factor behind melanomas, scientists are unsure of the exact cause. They can occur on parts of the body that have relatively little or no exposure, such as the soles of the feet, or buttocks. There may be a hormonal link because melanomas are twice as frequent in women as in men, and those that appear on pregnant women are unusually aggressive.

White people are 40 times more likely to develop melanoma than those with dark skin. People with fair skin, red hair, who burn easily, or who have a family history of skin cancer or a large number of moles - more than 50 - are most at risk. Having more than five blistering sunburns before the age of 20 doubles the risk.

The ABC of mole watching is a simple way to remember what the danger signs are:l Asymmetry (look out for irregularly shaped moles); l Border (a ragged, inflamed outline); l Colour (moles that are an even shade and become darker or mottled); l Diameter (any that grow - most moles are less than 5mm across).

There is hope of a cure. Earlier this year, a leading dermatologist, Professor Rona McKie of London’s St Thomas’s Hospital, successfully destroyed malignant melanoma in five patients by injecting herpes simplex virus, which causes cold sores, into the lesion.