I am writing this in the Peter Pan cafe at Great Ormond Street hospital, where my daughter had another bit of miraculous-seeming surgery last Thursday. I haven’t been home to change yet and am wearing a quite heavily bloodied dress and some sick in my hair. It’s the NHS’s 60th birthday this weekend and I’d just like to take this opportunity to get down on my knees and say thank you to the visionary spirit of Aneurin Bevan and to the heroic staff of not just this most admirable of hospitals, but to NHS workers everywhere, from the consultants to the cleaning ladies.

We are all familiar with the negatives when it comes to the health service, but there isn’t a country on Earth that could hold a candle to the overwhelming slew of positives. Every ward and outpatient clinic in this building is stuffed with people, some of them still in nappies (and some still in utero), whose lives have been saved or immeasurably improved by underpaid, overworked, heroic men and women (all drowning in mountains of paperwork, but that’s another story) who work insane hours and do unbelievably emotionally demanding work, simply because they want to alleviate pain and suffering.

The NHS remains the jewel in this country’s crown. We should all be bursting with pride that it exists, let alone functions as well as it does.

Rightly or wrongly, I’ve always been of the “if they hit, hit them harder” school. On the rare occasions (twice, as a teenager) when anyone has laid a finger on me, I have punched them in the face.

I don’t believe in turning the other cheek when you are physically aggressed. While never encouraging my two older children to get slap-happy for the sheer fun of it, my line with them was always: “If someone hurts you for no reason, hurt them back.”

I realise this isn’t terribly evolved and I wouldn’t expect my approach to delight the baby Jesus, but there you go. People have a right to go about their daily business without being randomly assaulted and I feel that assailants ought to be made aware of the fact, preferably via their solar plexus.

I still believe this in my heart of hearts. Unfortunately, my children no longer do. I have had to revise my “eye for an eye” theory, because not doing so would put them in danger. Over the past couple of years I have had to make a U-turn: hand over the money. Hand over the mobile phone. Give them what they want. Say as little as possible and for God’s sake none of your smart backchat. Don’t hit back. Forget hitting harder: what we’re after now is running faster. The words stick in my throat but I say them, over and over again, and I know I’m right.

The stabbing last weekend of 16-year-old Ben Kinsella – the 17th teenager to die of knife crime this year in London (an 18th was killed on Friday) – proves that conclusively. The streets simply aren’t safe and we must all become tremulous, cringing weeds if we are to have any chance of circulating unmolested. I can’t tell you how furious this makes me. Like most Londoners, I feel a kind of boiling indignation that I can’t put into words.

The greater question is, what are you supposed to do if you have teenage chil-dren? They know to meekly hand over their money/phone/iPod, but that’s the least of it. Kinsella – to pick one example at random: frankly, there is an embarrassment of choice – was out with friends celebrating the end of GCSEs. He was an A-grade pupil at Holloway school, one of those mixed big-city comprehensives.

Nobody tried to mug him, as far as we know – he was stabbed 11 times for no apparent reason (three people are in police custody, two aged 18 and one aged 19). He was killed in Holloway, one of those areas of north London that is also big and mixed; London, like many cities, being made up of little middle-class patches edged with little rough ones, or vice versa.

MPs, the mayor and publishers live in Holloway and so do feral young men who carry knives when they pop out for a drink. I expect this has something to do with the fact that Kinsella’s death has been the sole topic of conversation among middle-class London parents this past week: to be blunt, we are painfully aware of the horrors of knife crime but it doesn’t often happen on our patch.

This time it did. The comfort of distance is no longer present: nobody can say: “Dreadful black-on-black crime,” or “Oh well, gangs.” There aren’t any excuses or convenient patches of sand for our ostrich necks.

A few people I’ve spoken to have tried, rather desperately, to create one by saying: “What was a 16-year-old doing out at 2am [the time of the attack]?” The implication is that only useless parents don’t know what their kids are up to in the middle of the night and that their own offspring would, of course, be safely tucked up in bed.

Really? I wonder. Granted, not many people let their 16-year-olds roam the streets at 2am, but Kinsella wasn’t just milling: he was at a party to celebrate the end of exams. It’s true that 2am is pretty late, but then you celebrate the end of GCSEs only once in your life. The party, which took place in a respectable bar of the kind in which people celebrate their 50th birthday, probably ended some time after midnight. Allow a bit of extra time for postparty hanging out, plus a bit more for chat about who was going back in what direction and how they’d get there and you hit 2am with no trouble.

Two days after Kinsella was murdered, my 15-year-old son asked whether he could go to a gig in Camden Town – a similarly kind of mixed area to Holloway. We were all feeling rather stressed because his four-year-old sister was due to have surgery (see panel) and I thought that being out with his mates would cheer him up and take his mind off the dangers of general anaesthetics for kids with cardiac conditions, a topic he’d been brooding on for several weeks.

So I said he could go, didn’t (for once) tell him when to be back and took myself off to bed early – but not before noticing his phone lying forgotten on the kitchen table.

My son, having had a long rein for some time now, behaved perfectly. My point is that if you’re allowed to roam London pretty much as you please, stay out relatively late, hang out with your mates and so on, none of these things achieve the kind of thrilling, irresistible naughtiness that they do if you have a sheltered upbringing; ergo they are seen as normal and children don’t abuse their privileges – which is why my son, who could have stayed out all night without me noticing, came back at 10.30pm and went to bed. The irony – and the problem– is that these kinds of carefully thought out freedoms are also doled out carelessly to children whose idea of a good night out is to maim somebody.

What to do? Having done a giant turn-around on the “don’t hit people back” issue, I refuse to perform another one on the “go out and have fun but keep your eyes peeled” front. Caging your children for their own protection doesn’t do anybody any good: it just gives up the streets to nutters.

I honestly don’t think there has been a more dangerous time to be an overprotected teenager out on the streets: until the issue of knife crime is prioritised and resolved, all of our children need to acquire serious street smart know-how, pronto.

Educate your children, communicate with them, know where they are and trust them. The happy ending isn’t guaranteed but the alternative – children kept in gated communities, like fragile pensioners – is not an option in a sane society.

india.knight@sunday-times.co.uk

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