CHILDREN used to play games that adults could understand - time-honoured games with ropes, balls, or no props at all; games that grown-ups had played themselves, scuffing around in the street or rambling through fields. Now children are obsessed by games with names like F-22 Interceptor, Rescue of Princess Blobette, and Attack Sub: expensive games that need hardware, and software, and keep children indoors, on their own, hunched over screens and consoles.

'The Nintendo goes on as soon as they get in from school - before they've had a drink or a piece of cake, said 'Hi mum]' or been to the toilet. It's threatening Family Life As We Know It,' complains Jilly Thorpe, mother of boys aged 12 and nine. Many parents are increasingly worried that their children's most intense relationship is with the television screen, that modern children inhabit a bleeping, zapping world of electronic music and violent death, and have become largely incomprehensible, talking endlessly about 'shoot 'em ups' and 'multi-directional hack'n'slashes'. Adults have no idea what all this means, but suspect it is probably vile.

A series of recent health scares have bolstered this instinctive parental distaste. Several children have suffered epileptic fits after playing computer games: 14-year-old Samantha Gallop of Farnborough, Hampshire, collapsed after just 10 minutes of watching someone else play. In Japan, at least 121 people have had fits which were apparently triggered by the high-frequency flickering lights.

This week, a father who believes his son has been made ill by constant computer-games asked amusement arcade managers to ban him from their premises. Ross Newman, 11, from Bath, Avon, has been hooked for two years. 'Once I found him glassy-eyed, unable to hear what I was saying, and had to take him to hospital,' says his father, Ray. 'But he was regularly playing on the computer till 11pm, so it's not surprising.'

But take the junkie away from his screen (and it usually is his; girls may play, but it's boys who tend to get obsessive), and what is there left for him to do? Parents suspect that all the old familiar childhood games are fading from memory. At Dalbeattie primary school, Dumfries and Galloway, parents and teachers have gone to the length of reintroducing traditional Scots games, like peevers (hopscotch), and girds and cleeks (hoops and sticks), in an effort to counteract what they see as the poverty of playground culture.

Iona Opie, the chronicler of traditional children's games, has a new history out in a couple of weeks which suggests that the old games live on. The People In The Playground, a diary of eight terms in a Hampshire primary school, records skipping, kiss chase, and all the old rhymes to go with them. There is only one problem: Opie's research ended in 1983, when perhaps it should have started. The invasion of the computer game has really taken place in the last couple of years: Simon Morris, marketing director of Sega UK, says sales rose by 50 per cent in Britain last year. And if the British market, where penetration is estimated at 10 per cent of households, mimics the Japanese where it is 45 per cent, there is still a long way to go.

Products on show at the British Toy Fair, which opened at Earl's Court in London yesterday, suggest that no imminent let-up is likely. Barcode Battler, currently outselling the big two video games in Japan, will be available here from May. Sega's Mega CD is also out this year, offering much-improved graphics and real music. And the biggest, and to many, most threatening development of all, virtual reality - which will enable children to enter 3-D worlds, and 'experience things which before they have only been able to imagine' according to Morris - will soon become an affordable reality.

Parents inevitably worry that children will stop doing any imagining of their own. Whatever happened to reading, for heavens' sake? And what about roller skating; and tag, or tick; and French cricket?

One of the things that has happened is that we have summoned children in off the streets. 'At five or six I was walking to school; I won't let my own six-year-old out of my sight,' says Mike Edwards - 'not even for an instant.' We worry about vicious strangers, and probably even more about careering motor cars. And with childhood so constrained, small wonder children seize on the imaginative possibilities of Battletoads and Splatterhouse 2.

Iona Opie, however, believes parents are worrying unnecessarily. 'Some games do die out - some of the older singing games, and hoops, and whip and top. But many survive: there's still plenty of skipping, clapping, and chasing. We were always being told traditional games were dying out when we first started collecting them in the 1950s; but we found so many we had to do another book, then another. Part of the problem is that parents just don't see these games: they ask children what they've been doing, and they say 'Oh, mucking about.' So you get these scares periodically, often linked to crazes. But crazes are nothing new: there was, for example, a complete obsession with cup and ball in Regency times.'

In 1987, a group of teachers calling themselves the Physical Education Association distributed a pamphlet to schools called Let's All Skip, because they were so worried that children were becoming vegetables. Newspapers were suddenly deluged by letters from indignant children from as far afield as Northumberland and Hertfordshire retorting that it was impossible to get on the tarmac in their playgrounds during the skipping season.

Iona Opie also thinks parents overlook the vast acres of leisure children now have. 'The increase in gadgets in the home, prepared food, and smaller families all mean that children are no longer expected to look after younger ones and run errands. Earlier this century children were often working at the age of eight or nine, especially in rural areas, where they would come home from school and be expected to help look after the animals.'

In other words, there is now arguably more children's culture, rather than less. Certainly, the idea of childhood as a separate and different condition would not have been readily understood 50 years ago, when if children weren't doing anything useful in the house, they were tipped out into the street or park so as not to get in their mothers' way. Now middle-class parents report a ceaseless round of children's activities - art classes, football, riding, musical instruments, ballet, roller hockey, not to mention the constant staying-over with friends. After all that, they probably need some simple relaxation rather than improving activities. James MacIntyre, 13, says: 'I'd probably read more books and do more cultural stuff if I didn't play computer games.' Then he thought about it and added: 'I once lent my computer to someone and actually, I got quite bored.'

Geoffrey Goldstein, an expert in children's play, who lectures in psychology at the University of Utrecht and advises toy manufacturers, points out that parents are constantly blaming whatever new technology happens to be around for the supposed corruption of their sentimentalised view of childhood. 'In the 1930s it was comic books; then it was rock music - look at Tipper Gore in the United States, blaming rock lyrics for social breakdown; then MTV, now computer games. Children have an eternal need to play, and their play reflects to a large extent what is going on around them. If they don't play out so much any more, well, adults don't go out for evening strolls so much either.'

Parents tend to forget what their own childhood was like - 'great lakes of boredom,' admitted one mother this week: 'I did read a lot, but often it was junk.' Ian Brown, a psychologist at Glasgow University, says only a minority of children are really addicted to computers: 'I was probably as hooked as that on books - and I'm sure it de-skilled me more socially than these kids are de-skilled by computer games.'

And even the addicted get bored: Jilly Thorpe's children are now so adept at the games 'they go through them like a dose of salts. They don't get so excited about them any more.'

The main grown-up objection to computer games is that they are lone activities - just you and Ecco the Dolphin. But actually, says James MacIntyre: 'Everyone talks about computer games at school all the time - about tactics, and cheats, and the magazines, which everybody reads, and whether Sega's better than Nintendo.' In our house at Christmas, there was much enthusiastic conversation about best routes for Sonic the Hedgehog. And Julia Nicholls, mother of a 12-year-old who was playing for five-hour stretches until she restricted him, is now secretly rather pleased, because he has started contributing reviews of new games to magazines.

In one inner London primary school playground this week, Leo, nine, told me he liked 'the legendary games best: the ones with knights.' And what else did he like to do? 'I get into imaginary games, where I pretend to be a knight.' Almost all the children had a Game Boy or Game Gear, the hand-held bits of hardware, or one of the big consoles, and knew the names of the games. Daniel, 10, told me proudly that he had just sold his stock of old computer magazines for pounds 20.

But zapping dots on a screen wasn't the only thing that interested them. Large numbers of children were playing football, others were skipping, some were French skipping; some were playing hand-clapping games, and doing similar things with their feet. Watching them, it was completely incomprehensible to me why parents should object to computer games, which demand intense concentration, logic, and planning. 'When I go swimming I kiss all the women - flash]' screeched one group of girls in a clapping game, lifting up their jumpers. 'Dawn macherooshi pharoah,' chanted another lot mindlessly. If this is the golden past, give me virtual reality.

(Photographs omitted)