Tax relief should be offered on sports activities in efforts to combat the rise in obesity, doctors said today.

The Royal College of GPs (RCGP) called on the government to take action on obesity by making exercise affordable and accessible to everybody.

They also said that healthier foods should be available in schools to tackle weight problems among youngsters.

The call came as the government prepared to unveil its public health white paper which is expected to set out how it intends to halt the growing rates of obesity in adults and young children.

The RCGP was today holding a conference to discuss the costs of obesity, what doctors can do to treat obese patients and prevent people becoming overweight in the first place.

Rates of obesity among adults have almost quadrupled in the last 25 years, with 22% of Britons now thought to be obese. The number of obese children has tripled in 20 years.

Figures estimate that around 10% of six-year-olds are obese, rising to 17% of 15-year-olds.

Dr Graham Archard, chairman of the RCGP clinical network, said: "We need to create an environment where everyone is able to balance their busy lifestyles with healthy eating and exercise.

"With around 22% of the UK adult population obese this is an issue of growing concern to the medical community," he said.

Dr Archard said more needed to be done to ensure that sporting activities were available to everybody.

"Most people can't afford sports such as tennis at the moment, not when they cost as much as £5 a game.

"One idea might be to offer tax relief on exercise - after all obese people are likely to use more NHS resources than fit and healthy people," he added.

Today's conference, being held at the Royal Society of Medicine in London, will also hear from Dr Ian Campbell, chairman of the National Obesity Forum, and Imogen Sharp, head of health improvement and prevention at the Department of Health.

· Children in south Tyneside are being taught old-fashioned playground games such as hopscotch and British bulldog in a bid to promote "healthier well-being".

Explaining the move a council spokeswoman said: "By offering a range of fun, practical play activities that will enthuse children it is hoped that it will help them become more sociable and less competitive whilst maintaining a healthier well-being."