It was his first time. It always is. When the 18-year-old Christopher Preece overdosed on heroin at his flat in Didcot, Oxfordshire, his family believe that it was possibly the first time he had experimented with Class A drugs. And they know who was to blame: Amy Winehouse. Last year it would have been Kate Moss. A few months on it would be George Michael.

Preece was a lord-lieutenant cadet in the Sea Cadets, so the juxtaposition sits nicely. The upstanding young man, a credit to his family, led astray by these degenerate celebrities and their scuzzball lifestyles.

So this is how to take heroin. To begin with, dilute it in water, citric acid or vitamin C. Heroin comes as a powder, or as tiny rocks, so this is not hard. Do it on a spoon. As a first-timer, you will probably be using around 5 to 20 milligrams of heroin, so be careful. Use a small syringe, capacity 0.5-1 cc, to apply the liquid. You'll need it later, so keep it handy. Once the solution is mixed you may have to apply a little heat from below. Some forms of heroin require this, others do not. Ask your dealer if you are not sure. As a general rule, professionals - or addicts as they are more commonly known - recommend diluting white forms in water with heat, brown forms in citric acid or vitamin C with heat and pharmaceutical heroin just in water, without heat. Now you're ready to go.

A tourniquet can be applied to the arm to aid the intravenous process, but is not always necessary Using the small syringe, draw the solution through a filter - an unused cigarette end will suffice if cotton buds are unavailable - and aim the needle for the injection site. The median cephalic vein at the crook of the elbow is most popular, although some prefer the basilic vein at the top of the upper limb, which is easier to locate but contains a greater chance of nerve damage or an arterial nick. The hit will be fairly instant, 5 to 30 seconds. You may need to suppress the urge to vomit.

The point is: does this sound like the kind of process that an otherwise stable human being would enter into, just because he sings along to Valerie? Cooking, chemistry, self-mutilation, plus some fairly determined shopping to kick it all off. Forget the heroin, where would you get a 0.5cc syringe in a hurry without giving the game away? And vitamin C, that is at least a trip to the supermarket. Who wants that with a gram of smack burning a hole in the pocket?

It is a myth, the impressionability of teenagers where the deadliest drugs are concerned. Nobody becomes a casual heroin user. It is too much like hard work. It is the most determined act you will attempt all year. You think you've got it tough putting up shelves or laying a new patio? Try getting whacked out on horse. It is a commitment. It is the whole day gone.

Anyone who is not dedicated, anyone who is just going along with it because he thought Amy looked cool at Glastonbury, anyone who saw her rambling incoherently and fighting with her fans because someone hit her with a hat and thought “that is the life for me” - obviously without the fame, the money or the talent - that sort of person would bail out of the heroin lifestyle after the first awkward trip to the chemist in the high street.

In popular legend, dead drug kids are always hapless novices. In some cases, it may be true. Not many, though. Not any with heroin. We're not talking gateway here. Once you are involved with spoons and syringes, once you are impaling your arms and sourcing lemon juice like a Mediterranean chef, you are pretty much through the gate and on to the open highway, and don't start kidding people that George Michael led you there.

Nobody listens to him these days. Until he got caught with crack, most thought he was in the retirement home in the room next to Andrew Ridgeley. There was a huge outcry this week when it emerged that Michael had been given only a caution for possession of a class A drug. “What kind of example does this set to the children,” was the cry. Michael had his best years before any teenager was born. He is about as influential as Cab Calloway these days. And Winehouse isn't as big as bereaved relatives think.

“Young people see the likes of Amy Winehouse taking drugs and think they'll do it too and it will be OK,” Keith Preece, grandfather of Christopher, said. No, they don't. Drugs are around and young minds are inquiring. Nobody aspires to be her; they just look at what is available and think: “I wonder what those do?”

Boredom is the biggest curse for a teenager and drugs are a boredom buster. And drugs are not the answer, either, because they get boring, too, as listening to Winehouse's recent stuff will establish, but ennui and curiosity are why kids get involved. Christopher Preece was up all night in Didcot, playing computer games with two friends. Doesn't exactly sound like the road less travelled.

And on the subject of stuff that will get you killed, he was also in the Sea Cadets, a gateway armed force that sucks impressionable teenagers into the harder stuff, like the Royal Navy. As deadly as heroin if you don't know what you are doing, those guys. So just say no, kids. To all of it: just say no.

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