The number of cases of malignant melanoma among people in their fifties has trebled in the last 30 years, according to Cancer Research UK.

The charity reveals that almost 2,000 people aged 50-59 are now being diagnosed with malignant melanoma - the most dangerous form of skin cancer - every year, compared to less than 500 per year at the end of the 1970s.

This equates to a rise from 7.5 to 26.6 cases per 100,000 people.

Researchers say they are worried that, despite repeated warnings from health authorities, the increase is continuing - indeed the number of instances rose from 12,100 cases in 2009 to 12,800 in 2010, an increase of more than five percent.

Cancer Research is now working alongside the supermarket chain Tesco to raise £10m, which will fund 32 early diagnosis research projects across the UK.

Tesco is already providing funding for a team at the University of Edinburgh, which is examining new ways to alert people to the early warning signs of skin cancer.

The Edinburgh team, led by professor Jonathan Rees, are looking into using web-based images as a method to help people recognise abnormalities.

"People's idea of what skin cancer looks like is limited to three or four images that are widely used to promote awareness of the disease - but we don't think this goes far enough with helping people identify the problem and going to the doctor," said Rees.

"It's worrying that melanoma rates are on the rise. But, if caught early, melanoma can be treated very successfully so if we can develop a better system of encouraging people to go to the doctor, this could potentially save a great deal of lives."

Malignant melanoma was once the seventeenth most common cancer among British people in their fifties. It is now the fifth most common.

Vital first steps

Glenys Shankland, 57, from Derby, was diagnosed with a malignant melanoma in November 2010.

"When my husband spotted the mole on the top of my left arm that was very itchy and red, I didn't think any more about it," she said.

"I'm fair skinned and most of my family have red hair, so I try to be careful in the sun but I do enjoy being in the garden. I've been sunburnt a few times over the years, but I never thought it would put me at risk of skin cancer.

"Fortunately I was at the right place at the right time. We'd just moved house and I needed to register with a new GP so I mentioned the mole then. If we hadn't moved I probably wouldn't have gone to the doctor as I didn't think it looked like skin cancer."

Doctors were able to take action and remove the mole and surrounding tissue, ensuring that the cancer didn't spread.

A Cancer UK spokesperson said: "Melanoma is a largely preventable disease; people can reduce their chance of developing skin cancer in the first place if they protect their skin from sunburn."