Fear of a wide range of perceived dangers makes parents keep children virtual prisoners in their homes, inhibiting the development of vital language and social skills.
According to a new report from Barnado's, Playing It Safe, and investigations by BBC's Public Eye, poorer children are living the most restricted lives.
Nearly half of all parents interviewed said their children never or hardly ever played out without adult supervision. A total of 70 per cent said their neighbourhood was unsafe.
The biggest single fear for parents was danger from strangers. But despite some high-profile murder cases, the likelihood of children being harmed by strangers is quite small. From 1983 to 1993, an average 86 children under 16 were killed each year in England and Wales. Only five a year were by strangers.
Close behind was the fear of traffic. Here, children under 14 from the poorest section of society, often with nowhere else to play but the streets, are nearly four times as likely to die from injuries as those from well- off homes. Other worries were drugs, bullying and dogs.
The diminishing independence of children is illustrated by how children get to school. In 1971, 80 per cent of seven- and eight-year-olds were allowed to go to school without an adult. By 1990 this figure had fallen to 9 per cent.
While 69 per cent of the children interviewed walked to school, less than half (44 per cent) walked without an adult and they were all over the age of nine. Only 14 parents said they thought it would be safe for a child under 10 to do so.
By contrast, three-quarters of parents who said they walked to school as children did so before the age of 10, some walking as young as five without an adult. Only 16 per cent felt it would be safe for a child under 10 to do so today.
For most children, a life free of adult surveillance is virtually inconceivable and many suggestions made by them would increase rather than decrease adult supervision. Children said they wanted a warden to look after play areas, with one boy asking for "police walking with bulletproof jackets and guns".
Dr Ned Mueller, a clinical psychologist dealing with children, believes confinement can retard their intellectual development.
He says the danger arises when children live in a confined space, with no place to play unsupervised, have depressed mothers and lack attention. "People notice they can't talk. They can't make a tower of bricks either but what people notice first is language. They can be one to two years behind, sometimes worse."
Other problems such children can face is lack of memory development, and manipulative skills such as handling small objects. Social skills may also be affected, with children finding it hard to make friends. "If a child comes from a big family with not enough adult attention, he may feel very angry and may take it out on his peers ... our survival depends on social development. We have to take play and use it in the service of joining with other people or we are doomed," said Dr Mueller.
Barnado's is urging local communities and businesses to create safe play areas. Thirty-five per cent of parents said there was no playground in their neighbourhood, and of parents who said there was a playground, more than three in five said it was badly maintained. Most children play in their garden or yard (44 per cent) or on the street (33 per cent) with only one in five parents saying their children usually played on a playground or playing field.
"We must reclaim 'no-go' areas - once the bastion of children and now the domain of vandals, drug abusers and bullies - for communities," said Michael Jarman, director of child care at Barnado's. "All parents are worried about children's safety, but it is children from disadvantaged families that are most likely to be at risk when out at play and the least likely to have access to safe play facilities. In today's society, it seems fundamentally wrong that a child's chance of playing in safety should be affected by where they live."