Rising levels of obesity in Britain could lead to as many as 12,000 new cases of weight-related cancer each year by the end of the decade, a leading charity warned on Tuesday.

Cancer Research UK has calculated that if the rate of obesity rises in line with government predictions, many more cancer cases will follow.

“It is now well established that being overweight increases the risk of developing several types of cancer,” said Professor Tim Key, an expert on diet and cancer at the charity.

Government figures for 2003 listed 24.2 million people in Britain as overweight or obese. The Department of Health has predicted the number could rise by 14 percent, to 27.6 million, by 2010. The current population of Britain is just over 60 million.

Key said the growing number of overweight and obese women will have a higher risk of breast and uterine cancer, which are linked to the increased production of the hormone oestrogen in fatty tissue.

“We are less sure of the precise mechanisms in other obesity-related cancers but we can confidently predict that the number of these cases will increase unless the rate of obesity in Britain can be reversed,” Key added in a statement.

The charity said there is evidence of a link between excess weight and cancer of the bowel and kidney.

In addition to increasing the risk of cancer, obese people who develop the disease have poorer survival rates, possibly because the illness is more difficult to diagnose and is not detected until it is advanced.

The charity called for a comprehensive strategy to halt the increase in obesity and urged people to maintain a healthy body mass index between 20 and 25.

A BMI is the ratio between weight (kilograms) and height (square metres). A BMI of more than 30 is considered obese.

In addition to weight-related cancer, being overweight or obese also raises the odds of diabetes, cardiovascular disease and disability.