I moved this month to what, at first, appeared a quieter, more suburban area. The small local community, amassed on half a dozen side roads, are mostly friendly, hard-working Turkish families. At the corner of our road is the best Mediterranean restaurant in north London, and that, believe me, is saying something.

The first couple of weeks passed in blissful tranquillity. The man at the Red Sea supermarket actually introduced himself to us the first time we went in for milk. "Hi, I'm Saleem," he said, holding out his hand. "Welcome to the neighbourhood."

"Oh, right, yeah. Hi, I'm Lauren." The same thing happened in the newsagents with Ali. Before I could buy my daily pile of newspapers, I was treated to a list of local delights (fairs, parks, kebabs) and he outlined his policy on opening hours, too: "Open until my wife gets angry."

In the house next door lives a young teacher with a child of her own. We babysit for one another, have coffee and gossip over the fence. I've even baked a cake for old, crippled Henry downstairs, who lets us use his hosepipe to fill our paddling pool. For the first time in this city, I have real neighbours - am a real neighbour myself. With dreamy idealism, I wrote in my diary in our first month here: "This is a more working-class area than I've ever lived in before - and it's great."

But comradeship isn't the only thing walking the streets around here.

"'Scuse me, love, spare 10p for the phone?" the guy with rolling eyes asks me every morning as I buy milk. I've started to get in tune with the haphazard routines of the crackheads around here. You have to. Midday, they take a corner and beg. By late afternoon, they've had a hit. Never in all my experience of drugs have I witnessed anything so frightening as a crackhead directly after a hit. They are not human.

Yesterday, I was in the wrong place at the wrong time - outside the mini-mart. A woman, dishevelled and covered in blood, blocked the doorway.

"Luv, luv. Please, luv, got 20 pence in change."

"What for?"

"For the phone. My brother's been attacked, it's bad - look at me," she pulled off her dripping baseball cap. "There's a lot of blood. I need to call for help."

"Emergency services are freephone. You should call them."

"No, I need my mate to bring his medication . . . "

As I turned out my pockets, she hopped from foot to foot. I got a good look at her and what I saw made me sick with shock. She was excited, not scared. Sweat hung on her top lip and her eyes were wide with pleasure. I wanted to get away, but she gripped me by the hand.

"Thanks, I owe you, I owe you."

My two-year-old daughter was inside the shop, talking with Saleem and another man, whose combined smell of tragedy, sweat and urine were gag-inducing. He knelt on bare haunches, his clothes hanging in rags, and took her hand. As I stepped forward, he looked at me with a maniac's confidence.I calmly said: "Good girl, Alex, shake hands and come and look at these . . . these, er, peas over here." He held her hand a moment too long, and looked at me again for a reaction. All I wanted to do was get her home and wash her from head to toe.

This guy is not an addict. He has what the shopkeeper described as "bad head problems". Had he just taken his medication, or had he forgotten today? Is the whole world on seriously mind-destroying drugs? When did the idea that they might be start to scare me?

Valium, heroin and Mogadon were the enemies of family life when I was growing up. How lucky we are to have crack, temazepam and Prozac to deal with.