Can you hear that low whirr above our school playgrounds? Can you smell the tang of fuel permeating our university campuses? They are the after-effects of Britain's helicopter parents, who hover over their kids, ready to swoop when any risk or stress or spontaneity strikes.

These über-parents have had a starring role in a number of news stories recently. A company called Blue Tree Services is marketing GPS devices you can plant on your child. You will be able track their every move. 'He's left the Wimpy! She's gone to Asda! Oh my god, he's buying a copy of Heat magazine!' The company's managing director, Mike Smuts, says: "We have seen a huge demand for this product across all sectors of society."

Meanwhile, universities and graduate employers complain they are being bombarded by pushy parents. Dr Paul Redmond, head of the careers service at Liverpool University, says parents are coming to university career fairs to sell their kids – and if their kids aren't bought they want to know why. Huddersfield University has even had to set up a "family liaison officer" to save the Goldman Sachs stall from a horde of angry middle-class mothers and feed information to parents round-the-clock about their kids' progress.

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This smother-love is spreading so fast that it is causing a slew of social problems. Some are obvious: a major contributor to the rise in child obesity is the refusal of parents to let their kids outside – even though they are statistically no more likely to be kidnapped by a paedophile today than in 1958 or 1908.

But I see more subtle psychological shifts among my helicopter-fed peers. My parents were from the old working-class hands-off school of parenting – 'Let him walk! Leave him be! How else will he learn?' So I was bemused when many of my friends were never allowed out on to the street to play, or had their GCSE coursework drafted by their parents.

I was even more startled when I arrived at university to find it was still going on. So many people – especially the rich – had parents who were still managing their lives well into their twenties. University was once the breaking-point when even the most coddled kids could flee. Now mobile phones have become the longest umbilical cord in history.

I'd guess 20 per cent of British parents now count as helicopters, with many more veering towards it. The Californian child psychologist Dr Madeline Levine has produced the most detailed studies of the consequences after she stumbled across something that seemed paradoxical in her treatment of teenagers. "I found that kids from the wealthiest families had the highest rates of anxiety and depression and substance abuse, more than poor children," she says. "It just didn't make sense at first blush." Why would privileged kids be more miserable than poor kids?

She found that instead of being listened to and allowed to develop naturally, the wealthiest children were allowed no space to develop – except as carbuncles on the side of their parents' swollen egos. They were constantly driven from one "Enriching Activity" to another, micro-managed by manager-parents. Levine explains: "Paradoxically, the more [the parents] pour in, the less full many of my patients seem to be. Indulged, coddled, pressured and micromanaged from the outside, my young patients appeared to be inadvertently deprived of an opportunity to develop an inside."

It's an essential part of growing up to learn to take risks, get in trouble, and sort it out on your own. But helicopter parents are determined to strip any risk from their child's life. I have seen dozens of smart, sweet-natured people curdled by this parenting model. In the end, it produces two kinds of kids: the puffed-up, and the paranoid.

The puffed-up see the world as an extension of their parents' house. When the world is not laid out neatly for their pleasure, they are angry and confused. The Association of Graduate Employers last week issued a report saying that Generation Y – those born after 1982 – has a totally disproportionate number of "graduate divas", who "expect everything to fall into their laps". The report cited a typical case of a 21-year-old applying to work at a transport company who was overheard on the phone complaining to his mother. "I have got to go to London tomorrow," he whined, "and they haven't even told me how to get there."

Then there are the paranoids. They have been raised behind closed doors and taught to see the outside world as filled with unseen menace. The London-based clinical psychologist Dr Cecilia D'Felice explains, "I see young people in my consulting room all the time now who are incredibly anxious about life. It's learnt behaviour. They have been fussed over all of their lives, and they've internalised that parental anxiety. If you try to have a germ-free environment your child will actually get sick because she won't develop any resistance to germs. If you try to have a risk-free environment your child will become psychologically sick."

The rise in bulimia, anorexia and self-harm among teenagers is partly a product of all this over-parenting. As Dr Levene says of a typical teenage self-harmer she treated – a 15 year-old girl who carved the word "empty" onto her arm with an old razor: "She felt little control over what happened to her. Cutting was one of the few things over which she did feel control."

Why is this happening? Why have so many of the baby-boomers turned out to be baby-Führers, strangling their kids with their apron-strings? Their children are the safest who have ever lived. They are more likely to die in their beds of old age than any generation in history – yet their parents fear, constantly. There is no detailed research explaining this paranoia but there are some prosaic explanations.

Parents are having fewer children, later in life, often after gruelling fertility treatments. We live in a paranoid culture where every negligible risk is blown up by a 24/7 media into a drum-beat of doom. We live in a hyper-consumerist culture where we define ourselves by what we own. Children are inevitably drawn into this vortex, as another glistening status symbol. 'Have you seen my handbag? Have you seen my child?'

Whenever I talk to my friends' parents as they crash-land into their children's lives for another burst of command-and-control, it's clear this is not about their child's needs but their own. They need their children to be dependent on them (and Successful with a capital-S) because they see their kids as extensions of their own ego, not as separate individuals with their own lives to live. This isn't love. It is narcissism. It's time we told these middle-class Boomer parents: you need to grow up – or your children never will.

j.hari@independent.co.uk