TEENAGER Jonathan Wallace may be unusual in weighing 31 stones, but he is by no means unique.

Experts fear that the UK is facing a health timebomb because of the apparently unstoppable growth in the number of overweight people.

While the Government is trying to get us to take more exercise and eat more healthily, more and more of us are becoming couch potatoes.

Doctors have told Jonathan that he must lose weight if he is to survive more than five years.

Being grossly overweight places extra burdens on our hearts, lungs, skeletons and muscles and can reduce life-expectancy.

Things are already so bad that the equivalent of a home crowd at a Premiership soccer match die from obesity-related illness every year.

But the real worry for health experts is the increase in obesity among UK children.

The alarm bells began ringing last year when doctors at the Royal Hospital for Children in Bristol found Type 2 diabetes, normally only found in adults, in four teenagers who were all very overweight.

The finding suggests that the effects of obesity are being felt in children up to three decades earlier than they might normally be expected to develop Type 2 diabetes, a condition associated with heart disease, strokes, kidney and nerve damage, circulation problems and even blindness.

Dr Mary Rudolf, a child health specialist at Leeds Community and Mental Health Trust, has found that 30 per cent of 11-year-olds can be classified as overweight, while one in ten are clinically obese.

She blames the worrying trend on changes in lifestyles.

Recent research by Durham University has confirmed the decline in activity among young people.

After monitoring playgrounds at 200 North-East primary schools, sports scientist Dr Peter Warburton concluded that most youngsters appeared to be shunning exercise.

Last month, a plan was announced to recruit up to 25 overweight children and adults in Wear Valley to test the links between obesity and exercise.

The volunteers are to be asked to follow an exercise programme at Wear Valley District Council leisure centres, in collaboration with gym equipment company Technogym.

While the Government continues to call for us to change our ways, researchers at Leeds Metropolitan University think they have come up with a practical way of turning the tide.

Since the university opened a weight loss summer camp in 1998, it has helped hundreds of overweight youngsters to lose weight and acquire healthy habits.

Paul Gately, the director of the camp, said: "Our priority is to make these children happy and confident so that they can engage in activity and healthy eating and then their weight will take care of itself."

l For further details, go to www.weightlosscamp.org.uk or call 0113-283 2600.