How far away that seems. Such certainties have vanished. We yearn for ourselves and our children that imagined Arcadia we have lost. Ah, if only we hadn't taken that wrong turning in the Sixties and/or Eighties, the world would not be so stressful, dissolute, unsafe.
Viewed statistically, children today seem to be more of a problem than a blessing. One in three criminal offences are now committed by those under 18. Six per cent of young criminals are between the ages of 10 and 13. One in five British children suffers from a mental trauma serious enough to need treatment, Radio Four's File On Four revealed this month. Each year, 100,000 children run away from home, and steep rises are reported by various agencies in drink and drug abuse among 14- to 17-year-olds.
The age at which children surrender their childhood gets younger and younger. They are drawn into the adult world by the mass media, to appear on stage and catwalks and in TV commercials, and to consume pop music. There exists no coherent data from the record industry on how much the young teens and pre-teens spend on pop music, but their darlings and role- models, the Spice Girls, for example, have sold 5.2 million records in this country. A spokeswoman in the marketing department for their label, Virgin, says: "We don't need to count them. We know the very young are some of our best customers. They buy records and merchandise without worrying about what they're spending."
The clothes industry is less coy. The market in children's clothing was pounds 2.5 billion in 1994, according to the last Mintel report in 1995. Designers such as Paul Smith and Agnes B now devote entire collections to kids: cotton T-shirts for toddlers start at pounds 35. And Top Shop, Miss Selfridge and other stores, which once catered for the 18-plus, are now full of clothes for younger, self-consciously fashionable girls - girls like Mandi, a willowy 14-year-old.
Mandi is already a small-time model, so she's not wholly typical; but I suspect many, many other children would like to be her. When we meet, she is wearing dark mauve lipstick, which makes her incredibly full lips look bruised. She is undeniably beautiful, but also joyless. She smokes and talks endlessly. "What childhood?" she responds witheringly. "I haven't been a child since I was seven and my dad used to beat up my mum. I'm pretty, so she sent off these pictures. I do it to please her. But at least now I feel I am the boss."
She "hates" other models - they are "jealous like crazy" - and "being groped" by some of the photographers. And school, of course. But Penny, her mother, implores me, "You won't say anything horrible, will you? This is the best thing that has happened to us. I had a lovely figure once, you know. I was just a baby when I was her age. Mandi is already grown up. She'll be like Cindy one day." If you live in a top-floor flat in Baron's Court, this is the stuff of dreams.
Mandi used to cut her arms. She's stopped now. Still, her stony eyes and more bitter-than-sweet charm are unsettling. It's a look which would work well on the new Calvin Klein posters, where Kate Moss and other girls appear pallid, spent and defiant. "Heroin chic", as they call it.
Last winter, Vivienne Westwood's business partner, Carlo D'Amario, said he was "jubilant at the prospect of unleashing a band of untried innocents on the catwalk because they were sexy, chic and sophisticated". Mandi is not "sexy, chic and sophisticated", but she can look all of these things, which is not the same.
There are other people trading in such images who are twitchy about the effect they are having on young people. Most of the big modelling agencies I contacted refused interviews. Storm, which represents Kate Moss, Carla Bruni, Honor Fraser and other big names in modelling, did allow some access to one girl, but with a minder. Teenage girls, it seems, can thrust their bodies invitingly but cannot be trusted to talk to a journalist. Most are without guile, of course - because they are still children. Mandi, for instance, told me within the first five minutes that she had tried hard drugs. And sex? "Well, what do you think?" she said.
Sarah Doukas, the managing director of Storm, who discovered Kate Moss at JFK airport, is unusually open about her profession. She confesses that three of her young models have ended up in hospital with anorexia in the past few years. "You have to be very careful with young girls," she admits. "They need to learn self-discipline and to protect themselves from their own fears and temptations. Sometimes, it does sadden me that children are growing up so fast. It would be nicer if they could remain innocent. But the world has changed. What we think of as the time of childhood or adolescence is shrinking, maybe even disappearing. Kids do become streetwise very young."
The advertising industry thrives on such teenagers. Beautiful cherubs fill our screens and dreams with desire for that computer, that car: Buy a Vauxhall Astra because you love your wide-eyed toddler. There is a limitless supply of parents who would do anything to get their kids into these adverts, says Heather Morton, director of the Bubblegum child model agency. Few do it just for the money, apparently. For a TV commercial, the basic rate is pounds 45 per day - shocking, really, for an industry where millions of pounds flow between client and advertisers. Essex parents are particularly enthusiastic, says Morton - "they're very concerned to keep up with the Joneses". One dad rang up five hours after his son was born. "You have to remember that these are not people who can put their kids into private school and buy them a future," she says. "Life is hard, and they're absolutely desperate to give their kids something special."
And how. I try to remember this as I choke back my outrage in dullsville Hemel Hempstead one May Sunday, when hundreds of children - some as young as five - gather for their own Come Dancing competition. The faces of the girls are heavily made up, with glitter on their throats and hair; they wear Lurex, satin and stretchy lace gowns with enough slits and slashes to heat the breath of a nun. In their silver stilettoes, they thrust out their chests and wag their buttocks as their mums and dads, ordinary folk, huddle together, 10 hours at a time, drinking tea from their thermos flasks, eyes exhausted with anticipation.
This angst over lost innocence and childhood suddenly seems utterly irrelevant - and middle class. In this deeply divided country, for those left behind in the aftermath of the Thatcher revolution, whom education is failing and whose lives are so dreary that kicking in the side of a car must feel like a trip to Disneyland, activities like these offer a way out, a chance for children to be admired as individuals. As one unemployed father told me: "You are a failure. You sit in front of the box day in day out, for years. Your kids think you are worthless. Then I get Sam here into toy catalogues, and I can think: at least my kid might make it."
For many families, the moderate amounts that can be made by child actors and models can be a godsend. There are kids at Storm who have bought homes for their parents and who are paying to educate their siblings. Jodie, six, a model with Bubblegum, can feel privileged. She was born to a 16- year-old living in council accommodation. Life was pretty barren, says her aunt, Sue Cullen: "Jodie never had any treats, no holidays, nothing. She now travels to Europe, has nice things. She needed something to make her feel she was a somebody. She's had love, but that isn't enough in this day and age."
Katey Purkiss-McKendoo, mother of Molly, the lovely toddler in the Safeways television campaign, agrees: "We were finally able to get a new washing machine. The kids have been on a plane for the first time. We've put money away for them." They live in a forester's cottage, keeping chickens and goats. She says she is wary of making her daughter like "Bonnie Langford, trapped in a time warp", but she is sanguine about the future. "If this all goes tomorrow, that's fine. What hurts me is if people think I am just using my child for myself. I'd never do that."
Stories like these make it harder to condemn parents as plain pushy. Nor do stage schools, that other forcing-house for young talent, encourage such an attitude. I know, because my own son went to one. Far from preparing spoilt brats for celebrity, these are tough places, often run by warm, yet demanding, women who remind me of those inspirational teachers every ordinary school had before form-filling drained their energy. Go to the Barbara Speake School in Acton, west London, and there she is, Miss (not Ms, if you please) Speake, 68 years old, dressed in a pale-blue outfit, much dangling jewellery and delightfully tarty, pearl-blue pointed boots. Gentle June Collins is second-in-command. Her son Phil has not, she thinks, "done badly" since she dragged him to the school 30 years ago.
Even strapping teenagers quiver when called to their office, all impeccable in their grey and red uniforms. It is a wonder to watch. Miss Speake gets cross because the biscuits are brought in on a plate which does not match the teacups. Niceties must be observed. "We are what you would call upper working-class," she explains a bit grandly. "Our kids come from ordinary families. Many even go into debt to buy their children a chance."
Naomi Campbell started there, as did TV and stage star Brian Conley: his comprehensive school teacher once wrote, predictably, in his report, "Brian will never amount to anything". A video of a recent show performed in the school's shabby theatre has 10 West End Olivers singing together. At one point, Phil Collins leaps up to join them.
It must be admitted that they fare less well academically. This is one of the few schools to have been inspected by OFSTED, and it was judged by inspectors to be an abysmal failure for senior pupils, who obtained only nine per cent subject passes between grades A and C. Miss Speake is unrepentant: "We're trying to do something for kids who are not academic geniuses but have other talents which will help them make it."
Anna Scher's in Islington is another place where kids flourish; indeed, Kathy Burke, recent winner of the best actress award at Cannes, is one of many famous former pupils. Anna is a tiny Irishwoman with boundless energy and compassion. A thousand children a week attend her classes, and there is a waiting list of 2,000. Many are from homes where money is short.
The focus is not just on acting but justice, morality, equality and the responsibility that children have to make their lives and the world better. My son, now 19, went there and acquired extraordinary confidence, which helped him through the pain and confusion of his father and I divorcing.
In some ways, these schools are endearingly old-fashioned. Miss Speake claims that there has never been a single pregnancy or sex scandal in her school in 52 years - and "none of that flower power nonsense". At Anna Scher's, cool dudes sing "Catch a Falling Star" without blushing.
We may still grieve for a lost world of childhood, but it is remarkable that these children and their parents - even Mandi and Penny - have found a way of keeping aspirations alive, of continuing to fulfil life's longing for itself.
Holly Royal, 12, Elizabeth Smith Model Agency in Harrow
Her mum, Rosemary, likes to say that Holly is 13 or even 14. Age is all about how you look, she says. She's impatient because she wants her daughter to make it as a model and dancer, and the sooner she gets into the big world the better. She is just as ambitious for her younger one, Tiffany, who's nine. Rosemary passionately loves her blonde daughters.
Holly is tall for her age, and Rosemary is delighted that nature is helping move things along, but she is also awkward, shy and vulnerable. Through the thicket of enthusiasm that pours out of Rosemary, she assures me, in a tiny voice, that she enjoys the buzz of performance. She is sitting tight, with her arms firmly around her lacy blouse. She seems a very retiring sort of young lady to me, who would be happiest eating an apple and reading Little Women on a window sill.
"I'm not," she retorts. "I change completely when I'm working or dancing. I like people watching me and clapping. If my mum hadn't pushed me, I'd have just been playing football."
Rosemary says that real trouble is expected when Tiffany "finds herself". Tiffany, apparently, is already good at manipulating people. A scowl appears on Holly's face.
Rosemary thinks their agency is not doing enough to place her daughters. Miss Elizabeth Smith, for her part, thinks the girls are losing their natural grace, being groomed and gilded far too much. Each week, the Royal girls go to professional drama classes, ballet, tap dancing, modern disco and Latin American dancing, which can, Rosemary admits, make girls look "too adult, especially the way they move their hips and turn". She admits it's quite sexy. "But, hey, I'm very strict about that kind of thing. No going out late, no pierced bits."
Rosemary was a bunny girl once, and now she wants her daughters to do "glamorous things". She's frank about it: "I could have done much more with my life." She gives me a picture of Holly, taken when she was "biologically" nine, all soft and inviting in an Annie Oakley costume. For a moment, her excitement becomes infectious, her honesty refreshing: "You're probably going to say I'm pushy." I am, too. But no more so than the middle-class mother who cannot take a breath between ferrying her kids to ballet, horse- riding, piano and cello lessons, and tennis coaching. Rosemary just wants her kids to do well: "I don't want her to sit as a check-out girl in a supermarket."
What about education?
"I had friends who did their A-levels and they ended up at home with their babies, just like I did. Holly can try and make it. We are not thinking of other professions or choices. And, in the meantime, she can work in the family business."
"We rent out Scalextric trains for private parties. Phil Collins had one the other day."
Charlotte C, 16, model at Storm
When she walks in, there is nothing extraordinary about this girl, except that she is very tall and thin, with a belly so flat you could roll pastry on it. No make-up, her straight hair tied in a ponytail. Chatty and personable. It's impossible, really, to imagine her earning millions pouting on the catwalks and having tantrums. Then she opens her portfolios and the transformation is sublime: flagrantly provocative in one picture, ethereal in another.
She started at Storm while at school, working only in the holidays, a condition made by the agency itself. Teen models can expect to work from 10am to 6pm, with breaks. Her hopeless school results convinced Charlotte she had no academic future: "I'm one of those blonde bimbos. I have no brain. Imagine, I didn't even make it through Level One, Leisure Studies, for a GVNQ [General Vocational National Qualifications] - they were invented for no-hopers like me. It was the most boringest thing I have ever done. I live in this village in East Sussex, you know, where nothing happens. My mum runs a playgroup, and my dad works with computers.
"I don't think school teaches you anything but to be like everyone else. Sure, I could've become a nanny or something like that. But this is a real chance, I'm getting to live and grow. Before, you had to be rich, one of those posh girls with posh voices - what do you call them?"
"Yeah, those. Now even a country bumpkin like me can get in. I've been to New York, Paris. I've seen the most beautiful models in the world. It's quite scary, you know, when you're in the same shoot as Kate Moss. Nerve-racking. My mum comes with me, and it's great for her. We're treated so well. The photographers know how to bring out the best in you and, if you're young, you're treated in a very special way. I get so mad when I hear all these complaints about young models. Nobody forces you into nudity or that. Many of my friends have no future. I have, at least for now."
Barely 16, she claims to be earning many thousands of pounds a year: model rates can start at pounds 65 a day and very quickly rise to pounds 35,000 a shoot, for the right girl. "I'm not being big-headed," she says, "but now I know about money and have my own account. That's what all these big models are doing. They start their own businesses, they know that this is not a job for life; they have to make the most of it. Nobody can take me for a ride."
What about boyfriends?
"No way! They just want you for your money and to say they are going out with a model. I have better things to do with my life and my body."
Leon Pettit, 15, a pupil at the Barbara Speake stage school
Leon is very serious - about life, the future, making good. The son of an aircraft engineer and a housing officer, Leon is sure that, as a young black boy, he would have got lost in an ordinary comprehensive. One of his teachers, Jackie Miles, says that he's a "real hero" because he is so considerate; but, when he dances, he seems to me even more than that - like a spirit possessed by angels.
Humility has been drummed into him at his stage school. It's the quality you notice most, surprising in a world where the young are expected to be brash, loud and self-obsessed. "You want to be different, but you're never allowed to walk around saying you are special," he says. "Miss Speake would pull you down, and you don't want to get on the wrong side of her. She never forgets. You never get back in favour with her. Once, only once, she really shouted at me for 20 minutes, and I cried. She teaches you how to respect others and yourself, so she must be doing something right.
"In a big school, you'd get away with things. Here, because what you do is going to count when you go out to auditions and shows and that, you just behave like it's all really precious, you know what I mean?"
His parents own a house on a west London estate. On the sunny evening I was there, tough boys, black and white, were dribbling a football and killing time. They seemed dangerously torpid. But they had a smile and a wave for Leon.
"They're my friends," he says. "They never tease me about my ballet and tap dancing and that. I think they know I'm serious. But I don't want to be hanging around like them. My mum and dad have worked hard to get somewhere. I'd love to be a professional dancer. If that doesn't work, I'll go to college and study photography. But now I'm just happy that I've been in The Bill and The Bizz - and the C&A Ski show catalogue. That was great.
"I know that being black is a problem, if I want to carry on modelling or acting. Even Naomi Campell suffers They often want some blue-eyed blonde. But so what? Now it's all opening up, and you can't just sit there and not try. I know there'll be failures. But I won't break like kids who can't deal with rejection. So even if you never see Leon Pettit up there in lights, I'll be OK. I'll do something with my life."
Becky Smith, 15, Barbara Speake
Although she attends the same school as Leon, Becky is more circumspect, less driven, but just as gentle and communicative. When she speaks, her London accent leaks through the "proper" pronunciation she is taught: "I'm always being told to put the endings on my words. But it's hard."
She has been at Barbara Speake since she was five. Her brother, Ben, is also a pupil and has appeared in Les Miserables, Annie Get Your Gun, and The Madness of King George. Becky has been in Hale and Pace, The Bill and a panto at the London Dominion. Their dad fits office furniture, their mum looks after the youngest child at home. They all live in a small, terraced house near Heathrow Airport.
"I don't want you to think that my mum is pushing us," she says. "If we didn't want to be here, we wouldn't be. I think some girls my age, even my mates, think I'm weird - you know, a bit proper, like. I have never tasted a cigarette, would never do drugs or drink. Not the other thing, either. Sex, I mean. But I really don't care what they think. I'm not like them. I feel really sure of myself. I don't do things to be part of the crowd." She's in danger of giving teenagers a good name.
She prattles on, delightfully spontaneous. "Maybe I'd have been like this at a normal school, too. But I do sometimes think that at a normal school I would have looked at more choices for the future. I think girls are being forced to grow up too much too soon. They start using make-up at 10 and 11 and wear all those revealing clothes. But then sometimes I see some of my schoolfriends in shows and I think we're part of that whole thing, too."
Would she send her own kids to a stage school? "I don't know. You can see that it can make some kids very big-headed. Even the way they walk. I hate that. You see some of them and you wonder what will happen to them when they are on their own in the big, bad world and they behave like they're stars or something.
"But I think it makes me strong enough to understand that life is tough and anything can happen, even if you're really talented. We go to auditions and do our best, and then we're taught that just because you didn't get chosen, it doesn't mean you are no good.
"It's amazing how important that is. I know young girls who have no self-confidence. If a boy doesn't fancy them or they think they're ugly, they really lose what they are. I'd never do that."