Children are being denied the ‘sheer joy’ of being outdoors due to health and safety fears, the head of the National Trust warned today. Dame Fiona Reynolds also said that cosseted upbringings are also damaging youngsters’ fitness and weakening their immune system.

Figures show that children are now three times more likely to injure themselves by falling out of bed than from a tree and that unsupervised roaming has shrunk by 90 per cent since the 1970s. Dame Fiona said applying the health and safety culture of the city to the countryside was wrong. ‘The world has become a very different place, and people have become very anxious about the risks – real or perceived,’ she told The Times.

There have been a spate of warnings in recent years about young people’s lack of exposure to nature. A 2009 report for Natural England showed that only 10 per cent of children now experience woodland play, as opposed to 40 per cent of their parents’ generation. The National Trust, which represents 4million members and maintains millions of acres of countryside, is marking the centenary of the death of Octavia Hill, one of its founders, who fought to preserve public open spaces in London and elsewhere. They are launching a campaign to give children a greater chance to play outdoors.