The open spaces where we played are cruelly lost to today's children

Do you ever feel like you are living in a dystopian novel by JG Ballard? I know that I do. Take last Monday, when I found myself at Marseille airport, the interview I'd been doing having finished too late for me to fly home. I'd had the foresight to book a room in a hotel that I would be able to reach by means of a handy 24-hour shuttle bus but on the night I was suddenly reluctant to take advantage of this particular 'courtesy'. For one thing, I'd spied the hotel from the coach I'd caught from the city, and thought it could not be more than a five-minute stroll from the terminal. For another, it was a balmy evening. Daringly, I decided to walk.

What followed might have been funny if it hadn't been so frustrating: an obstacle course for the mind as much as for the body. At first, I took the various hurdles in my stride. A busy car park. A series of mini-roundabouts. The forecourt of a petrol station. When motorists hooted at me, I tried to look nonchalant, swinging my bag jauntily, as if this was a route I took every day. When the hotel sign was in clear sight, my spirits soared, a weird sense of achievement rising inside me.

But my journey was not over yet. Ahead, the road was bordered only by a narrow verge. Could I struggle on, tightrope walker-style, one foot daintily in front of the other? I could not. One false step, and I'd be killed by the next whizzing Peugeot. Pretty soon, I was back at the mini-roundabouts – dusty by now, and in low spirits. Pretty soon after that, I was on the courtesy bus, listening to Mantovani.

It's thanks to episodes like these – such stifling crises seem to occur ever more often in my daily life – that I didn't feel remotely surprised by the news that rickets is on the rise in British children. My amazement is, I'm afraid, reserved only for those who consider this development amazing. Nor do I regard the return of rickets as particularly 'Victorian'. Of course some of those who are suffering – alas, the chief medical officer, Professor Dame Sally Davies, did not marshal any statistics when she called for children under the age of five to be given vitamin supplements – must owe their condition, at least in part, to a poor diet. But the single best source of vitamin D is sunlight on the skin. Twenty-first century rickets is, it seems to me, an ultra-modern disease, being so obviously a result of the airless, indoor world we've created for ourselves. After all, it's not as if children are the only ones. Anecdotally, vitamin D deficiencies in adults are on the increase, too.

Of course it's foolish for columnists (or anyone) to measure progress using the yardstick of their own childhoods: rose-tinted spectacles are the blurriest of goggles. But since I mostly hated being small, I'm perhaps better placed than some to spot the few things that really were better. And if I had to highlight only one change, it would be our attitude to the outdoors. Where once there were dens, now there are iPads. Where once we had long summer nights, now we close the curtains, the better that the sunlight does not fall on our screen. Children and adults alike are stranded indoors, pale as mushrooms under the stairs, connected to their peers solely by various technological devices. Those of a certain sensibility ascribe the lifestyles of our children to their parents' Daily Mail-stoked fears: to traffic, to dangerous dogs, to gangs, to paedophiles. But beyond the headlines, it's a material thing. If most adults must move seamlessly from one air-conditioned space to another, why should their children be any different?

The topography of our urban spaces works cruelly against us – and not only in the case of airports. Street furniture inevitably obstructs (the railing you will always hit should you try to cross dual carriageway); spaces that were public are suddenly and slyly re-engineered by private companies (see Liverpool One, developed by Grosvenor, a company owned by the Duke of Westminster, which sprawls over what used to be city streets); buildings come down and go up with disorienting speed, destroying forever favourite rights of way. If fear does play a part in our reluctance to walk outside, then this is mostly the fear of other people's fears. Will your hothousing friends freak out if you send your small boy out to the corner shop? Perhaps, and almost anything would be better than that.

Not so long ago, I walked from my parents' home to my old primary school, an establishment whose chief virtue – its only virtue – lay in the fact that it was set in vast playing fields and had wrap-around playgrounds (formerly with wooden barrels in which one could climb, but now with – dread words – 'soft play areas'). No time for sweet nostalgia on this outing, though. I could not look through the windows at the hall, the kitchens, or the children's paintings on the wall. I could not even lie in the long grass at the edge of the playing fields and stare at the sky. A forbidding metal fence had been erected around the perimeter of the entire site, as if it were a prison.

I went home raging. Is there a sorrier sight than playing fields that are empty on a Saturday morning? They might as well build houses on them, and have done with it. According to my mother, the school had decided that the risk of a parent suing was just too great. Suing over what? I asked.'Oh, if some divorced dad wanders in and takes their child…' Thanks to this scenario – convoluted, and vividly imagined, almost as if some staff were hoping for such Kramer vs Kramer excitements – no child may make use of the school's facilities during the long summer holidays.

What is to be done about all this? The answer is: very little. Ballard knew what he was doing. It's just that some of his futures have arrived more quickly than others, the bleakness expanding exponentially, the bollards and the crash barriers, the fences and the signs, breeding like any other kind of pest, which is to say with great vigour. So many places, from city squares to airports, have dispensed altogether with the concept of people with arms and legs that swing and stride, with bodies that need to move, and eyes that want to look, and souls that yearn for a horizon, or even for a mature tree. Rickets is only the beginning of it, believe me. Curing the sickness that lies ahead is going to require an awful lot more than vitamin pills.