Multiculturalism? Yes, things are getting better. But, says Howard Jacobson, beware irate shoppers in supermarket car parks and young women bearing smiles
Sad that it should have taken bombs to remind us that we are one community. Multiculturalism isn't the ideal word for it, but the truth is we are beginning to get the hang of variousness in this country; at our best - on warm evenings in Brixton and Brick Lane and Soho - we even revel in it, loving the perfumed mix, the Babel clamour of every persuasion eating, drinking, playing, as it chooses. So yes, in the face of maniacal hatred, let's all link arms and promise that no one will ever come between us.

In more peaceful times, though, the amity can be harder to sustain. A particularly noxious weekend - a villainous entry in my own diary of ethnicity - comes back to me. It was four or five years ago. Christmas. South London. I was doing the shopping.

To be exact, it was the last Friday before Christmas. And I was shopping at Sainsbury's. Or I would have been shopping at Sainsbury's had I ever made it past the car park.

I had a long shopping list in my wallet. That may have put me out of temper. I don't like lists which extend to both sides of the envelope. But I don't think I was that much out of temper. No more than anyone else who had queued 40 minutes to get into Sainsbury's car park, and then driven around for a further 40 looking for a space. Yes, yes, our own fault for leaving the Christmas shopping so late, but who, behind the wheel of a car, has ever accepted blame? We were human: we took our frustrations out on one another. We honked our horns needlessly. We made it difficult for other cars to reverse. We parked inconsiderately, so that no one on either side of us could get in or out. That's when we were able to park at all. I missed three medium/difficult chances myself, and two easy ones. My final try was borderline. Borderline difficult/easy, and borderline in the sense that a second driver thought it was her's as much as mine. She was wrong. I'd been waiting longer. I'd exchanged interrogative gestures with the returning shopper. But she thought otherwise. While I was allowing the car already in there to back out, she made her move from the opposite direction and got her nose in before me.

She wasn't in uncontested possession. She'd swung in too sharply, leaving me a tiny, spoiling space to shove my nose in as well. Stalemate. Our noses touching. No collision. Just touching. You know what happens next: shouting, swearing, accusations of idiocy and evil, and a minute forensic examination of both bumper bars.

Except that I didn't do that. I just sat there. Dumb insolence? Maybe. But I felt aggrieved, and have never been that much of an unscratched- car lover anyway. She, however ... Well, she charged me with malice aforethought and worse, racial harassment. She was African-Caribbean, very fine to look at, with piercing green eyes and wonderful cheekbones. Does it matter what she looked like? Only in the sense that I liked what she looked like. Trouble was, she didn't like what I looked like. "You people," she shouted. "Typical of you people!"

Who did she mean? Men? White men? White men who are late with their Christmas shopping? Semites? Could she mean Semites?

I told her that the space was indubitably mine, that she had stolen it, but that I would nonetheless let her keep it - "Have the fucking space," I may have said, for I was angry to be called "You people", whoever she meant. Then I wound up my window and put the car into reverse. It can happen when you are an exasperated white male Semite late with your Christmas shopping that you mistake your forward gear for your reverse gear, and your accelerator for your brake. The car leapt forward. Still no damage, but this time she could accuse me of trying to run her down.

"Did you see that?" she appealed to the African-Caribbean kids working the car-wash. "Did you see what he tried to do to me?" They had. They had seen it with their own eyes. And now what I saw with my eyes was myself at the Bar of the Old Bailey, on trial for deliberately attempting to run over a black woman. Bonfire of the Vanities, Nine Elms. I wound down my window. But before I could say a word in my own defence she was there, hitting me, raining blows on my face, 10, 20 punches, none of them damaging to my skin, but all of them injurious to my heart. I drove home blanched and shaking. I had not done the Christmas shopping. "I have been caught up in a race war," I told my wife.

"It looks like it," she said. And put me to bed.

The next day I tried again. A less demanding, local shop this time. As I was leaving the butcher's, loaded with festive game, I saw a young woman coming my way, smiling. I knew that smile. It was a reader's smile. A fan's smile. She would approach and tell me which of my novels was her favourite. Now a man of sense knows never to meet a smile of that sort. Nothing more humiliating than to catch yourself doing the avid star thing - searching for recognition in the face of a fan. But I was needy from the day before. I opened up like a flower.

"You Jew!" she said, and walked on.

I stood rooted to the pavement, insensible. Could I have heard her right? I started to chase after her, shouting, "What did you call me?"

I caught her in a chemist. White, young, strong cheekbones. And not frightened. "You heard me," she said. She was at the cash desk, paying for toothpicks. "Go and shower. You know the sort of shower I mean."

A gas shower? Did she mean a gas shower?

What could I do? Punch her?

I arrived home blanched and shaking.

"Another race war?" my wife asked.

They happen, that's all I'm saying