Why have I started lecturing people in the streets? Maybe because I consider it a form of public service "That's not lecturing," my wife tells me. That's preaching. Preaching! Why is it preaching when all I am trying to do is warn young women that if they go on wearing 6in heels they'll be lame by the time they're 40, that's if they haven't already walked underneath a truck while tweeting about Robbie Williams, an interest in whom is not compatible with live brain activity? "There you go again," my wife says. I recently saw a woman drop a scarf in Trafalgar Square. It was bright red and lay like a splash of blood coughed up by one of the lions. I bent to pick it up but I'm a slow bender and by the time I was upright she was halfway across the square. I took off after her, shouting "Madame!" - a word she'd probably never heard before - then tried "Miss!," "Lady!," "Mrs Woman!" (an expression from my father's market days), and finally "Izvineetye, your babushka!" on the reasonable assumption she was of the same nationality as everyone else currently traipsing around London. No response. If anything, her pace quickened. My bad luck that she was the only woman in Trafalgar Square not wearing 6in heels. I had to run to catch her in the end. I tapped her on the shoulder, When she turned I saw that she was wearing headphones. Now I have been careful about inveighing against the wearing of headphones in public places ever since a person apparently wired up to the usual musical inanities walked blindly into me, stopped in amazement and, before I could dress him down, told me that by wonderful coincidence he was listening to my latest novel on audio book. I let him off with a caution. But on this occasion I could think of nothing but the madness of making yourself so deaf to the world that if someone tells you that you are on fire you can't hear. Not waiting for her to remove the cans, I took her arm and told of the risks she faced. "It isn't only that you won't know when you've lost something," I shouted, "but when the driver of that bus over there suffers cardiac arrest you won't hear it careering towards you; you won't hear the mad cyclist (not that there's any other kind) ringing his puny bell and abusing you for being a pedestrian; you won't hear air-raid sirens, bells tolling, buildings being blown up by terrorists, a plane falling out of the sky. . . Apart from which, why seal yourself away like this, why deny yourself a faculty, why shut your ears to the multifarious sounds of the city, the very carnival of existence itself, for the sake of a tune you've listened to a thousand times already? Do you have no conception of quiet? Is it really inconceivable to you that your head might want to think its own thoughts unmolested by the monotonous beat of a band you should be ashamed to have heard of let alone to call your favourite? Little Mix! Are you quite mad? I like your scarf by the way. Though she had no English I didn't doubt that had there been a policeman close to hand she'd have summoned him. And then a family of Italians stops me on Haymarket and asks the way to Abercrombie and Fitch. There are four of them, mother, father, and two daughters aged somewhere between six and 30. They are well-dressed, in possession of a bella figura apiece, the mother swathed in furs, and wheeling suitcases. I want to ask them why they aren't in a taxi. Why people cart luggage through the streets of London when there are plenty of taxis, and taxi drivers know where Abercrombie and Fitch is, I don't understand. Are they saving money? If they want to do that why don't they buy cheaper tickets for Charlie and the Chocolate Factory or Mamma Mia!, or better still no tickets at all. They must know people who have sat through these trumperies. Are their lives perceptibly better for the experience? Do they have an inner glow? And there is something else they can do to make their time in London more pleasant, to avoid having to shlep through the West End wheeling cases, wondering where Abercrombie and Fitch is - they can not bother going there. "Aberzombie and Filch," I joke to my wife whenever we pass the shop in question. She is not amused. What I mean is that the young are being stolen from by a cynical fashion industry that turns its customers into zombies. Tourists wearing the expressions of the undead queue outside Aberzombie and Filch in all weathers in order to take photographs of themselves queuing to buy identical t-shirts and gawp at half-undressed California boys with muscled torsos. "You can get that at home without queuing," I tell my wife who still isn't amused. I refuse, anyway, to show the Italian family where the shop is on the grounds that their daughters should not be encouraged in their avidity, their conventionality, and their Grazia-driven concupiscence. "Why not take a taxi to the Wigmore Hall instead," I say, "or Hatchards where you can buy your girls a novel each by Dickens and return them to their innocence." I don't know if that's preaching, but if it is, someone has to do it.