The number of young people with bowel cancer has more than doubled in ten years.

Obesity and lack of exercise are blamed for the 120 per cent rise in cases among under-30s between 1997 and 2006.

Experts said the 'astonishing' figures showed the disease was no longer the preserve of the elderly.

Professor Will Steward, a bowel cancer expert from Leicester Royal Infirmary, warned the number of cases was likely to continue to increase.

He said: 'This is an extraordinary rise in a group of people who virtually never got colon cancer ten or 20 years ago. The causes must be confirmed by the Department of Health but I suspect that children's changing diets, with increased fatty and high-calorie meals, are fuelling the rise in bowel cancer at such a young age.'

Answers to parliamentary questions show that 63 people under the age of 30 were diagnosed with bowel, or colon, cancer in England and Wales in 1997. By 2006, the figure stood at 137.

Hilary Whittaker, of charity Beating Bowel Cancer, which obtained the figures, said it highlighted the need for better awareness of the disease.

'Half of the people who are diagnosed will die,' she added. 'It is the second biggest cause of cancer deaths.'

Bowel cancer claims around 16,000 lives a year, with only lung cancer killing more.

Symptoms include persistent changes in bowel habits, abdominal pain and bleeding.

Sarah Collins, who lost her brother Richard to the disease last year aged 29, said it was wrong to dismiss the illness as an 'older person's disease'.

Richard, who lived in Cambridge, was told he was 'too young to have bowel cancer' when he first complained to his GP of diarrhoea and a swollen stomach.

Miss Collins, 27, said: 'This terrible disease claims 50 lives every day in the UK but too often bowel cancer is thought of as an older person's disease.

'We need to dispel that myth  -  people of all ages should be made aware of the symptoms and persist with their doctors if they are fobbed off.'

The World Cancer Research Fund warns eating processed meat  -  including bacon, ham, pastrami, salami and hot dogs  -  significantly raises the chances of developing bowel cancer. Red meat also raises the risk slightly.

Eating plenty of fruit and vegetables, fish and wholegrains can cut the risk. Taking regular exercise and giving up smoking are also thought to reduce the chances of getting bowel cancer.