No matter how you look at them, the statistics are startling. The British Heart Foundation's 2000 report, Couch Kids: the growing epidemic, found that over a third of children aged between two and seven weren't achieving the minimum recommended exercise level of an hour of physical activity a day. It also revealed that children were spending more time than ever before engaged in sedentary activities such as watching TV and playing computer games: 10 hours a week for two to seven year-olds rising to 17 hours a week for 13 to 15 year-olds. But as Britain faces up to an alarming rise in obesity, what can be done to counter the 'couch kid' culture? And will it be enough to produce active adults?

Childhood obesity is flashing on the political radar. According to Couch Kids, 20 per cent of four year-olds in the UK are overweight and eight per cent are obese. Things have almost certainly got worse during the three years since these figures were published â?" in the past decade the number of obese six year-olds has doubled and the number of obese 15 year-olds has trebled.

Sports minister, Richard Caborn, has referred to the immense health consequences of this trend as a 'ticking time bomb'. Not only are overweight youngsters more likely to become overweight adults, but also the earlier health problems associated with obesity start the shorter life expectancy is likely to be.The emergence of Type II diabetes, normally restricted to the over 40s, in overweight children as young as eight is an alarming example of the extreme health problems the future could hold. The ever-growing list of conditions related to obesity - heart disease, high blood pressure, diabetes, strokes and hormone related cancers - has become a familiar litany. Treating obesity costs the NHS around £500 million a year and the cost to the wider economy is more than £2 billion through illness and premature death.

We all know that it's a simple equation: the fundamental cause of obesity is consuming more calories than are used in daily life. The message is eat healthily, exercise more. Yet our young people are increasingly inactive. In Sweden children participate in, on average, 10 hours of sport a week. Here in Britain, the government's aim is that 75 per cent of schoolchildren should take part in two hours of sport a week by 2006. Currently only one secondary school child in three is achieving this goal.

It would be easy to blame the schools. But physical education has been squeezed out of the school day by the competing demands of the national curriculum, and playing fields have become valuable assets that continue to be sold off as head teachers face the impossible dilemma posed by budgets that don't add up.The government's national strategy for sport, launched in December 2002, includes a £459 million investment programme for school sports. At the centre of the strategy is a network of specialist sports colleges, each employing a sports co-ordinator to work with other local schools in sharing facilities and raising standards. From September 2003 an additional 28 specialist sports colleges will bring the total to 229.

An Ofsted report launched in June has welcomed sports co-ordinators as 'a positive catalyst for change' and noted that schools are working hard to offer their pupils a wider range of sports. However, the report warns, that a quarter of school PE lessons are unsatisfactory and states that: 'Although schools are giving more emphasis to the teaching of PE and school sport, the quality of teaching remains a concern as the proportion of unsatisfactory lessons is too high'.But it's not only in school that children are less active. Parental fears mean that many children spend more time on a PlayStation than in a playground â?" the perceived fear of child abuse outweighing any consideration of the future health implications of inactivity. The number of children walking or cycling to school has dropped dramatically over the last two decades. In the mid-1980s, two thirds of children aged between five and 10 years walked to school, but by the late-1990s this had fallen to just over half. Time-constraints and safety concerns overcome unease about pollution.

And it's not just parents who need to take action. The Children's Society and the Children's Play Council have warned recently that 'intolerant adults' are preventing children from playing outside. Research involving more than 2,500 children cited 'no ball games' signs and adults telling children off for making a noise as barriers to outdoor play.

The physical benefits of exercise are well documented, but there are other reasons to encourage school sport. A recent Strategy Unit report, Game Plan: a strategy for delivering government's sport and physical activity objectives, cites the preliminary results of an ongoing investigation by the Qualifications and Curriculum Authority indicating that: 'Schools with good records in physical education report higher achievement across the curriculum. Schools with high participation in sports also tend to have lower truancy rates and better behaviour.' The link might be harder to prove, but few would doubt the increase in confidence, self-esteem and social skills that many children gain from organised sport. But will exercise at a young age continue into adulthood? Currently 70 per cent of children give up nearly all physical activity as soon as they leave school. Clearly, encouraging children to exercise is just the first step.

But Game Plan asserts that: 'Giving young people a solid, enjoyable start to sport and physical activity is the best way to develop 'sports literacy' and engender lifelong participation.'