More of them are obese than ever before, the rising problem on knife crime threatens to turn many into victims and even when it comes to the very basic tests, the failure rate is high.

A survey by the National Trust was the latest in a series of reports designed to tell us what we probably already knew – children are out of touch with real world.

Apparently, half can't tell the difference between a bee and wasp and wouldn't know a magpie if it came up and introduced itself – but ask them about Dr Who's Daleks or Jedi Grand Master Yoda and they will happily tell you more than you ever wanted to know.

For many, the results were further evidence of a sad modern phenomenon, but can anything be done about it? Over the next three years, the Government is investing £225m in outdoor play areas. While its harshest critics might point out that with many playing fields having already been sold off to the highest bidder, it's the least they could do, it's a policy many would struggle to oppose.

The problem, however, will be getting children to use the new facilities and will test the well worn response to anti-social behaviour and general inertia that young people simply don't have enough to keep them entertained. However, if the malaise does continue, we might all be in trouble.

"Children need to go somewhere where they can test their boundaries," says psychologist Jane Prince. "It's very difficult for a child in a constrained place to get a sense of what they can and can't do, and that can produce either very timid children that don't test themselves, or very unrealistic children who are convinced they can do anything.

"If kids play outside in an environment where they're not controlled and which isn't defined by the quality of the product – as it is when they're playing indoors with toys – they can start to experiment and explore what they can do for themselves.

"It's risky in the sense that you can't contain your children when they're playing outside, even if you're with them and monitoring them. But if children don't explore what they can and can't do, they'll never understand the limits or the possibilities of their own environment."

Ultimately, of course, it comes down to parental responsibility, but research has shown that, living in a fantasy world of computer games and cartoons, children never learn to appreciate that sometimes other people's rights take priority over their own.

"When children are outside, they look at things growing, they look at animals and flowers and plants, and touch things that don't feel the way things in the house feel," says Jane. "They also learn not to be frightened of nature and that a spider or a worm isn't really that terrifying. They engage with their own planet, by running around open spaces and getting down and getting dirty.

"I know parents are stretched for time, but just say, 'This is what we do', and make it a weekly or fortnightly occurrence."

Last year, more than 100 academics, authors and charity leaders signed a letter to the Daily Telegraph warning that children's health – particularly their mental health – is suffering because they're losing the chance to play outside.

"Children learn through first-hand experience of the world, not through staring at screens," says Sue Palmer, the author of Toxic Childhood: How Modern Life Is Damaging Our Children, who organised the letter with child mental health specialist
Dr Richard House.

"One of the problems with parents nowadays is they feel they've got to keep their children entertained every single minute, but children – particularly the younger ones – will play happily in outdoor spaces without needing any assistance at all.

"We've been groomed to think that anything that's worth having has to cost money. But the things that really matter for child development don't cost anything.

"Children still need the things they've always needed – for millennia – and you can't provide that within four walls with a
TV screen."