They're back. It's December and they're clogging up the capital with their carrier bags. It takes half an hour to walk the just under half a mile from Piccadilly to Oxford Circus because they're all over the pavement, gawping at the adverts for We st Endmusicals as though they've never even seen electricity before. Bloody provincials.

The worst of it is that when they get home after trying on all the scents in Selfridges, they'll sit in their living-rooms in Nether-Wittering-in-the-Mire, brushing dog hairs from their jumpers and saying: "It was hell. I'll never go again. The crowds. The pushing. People are so rude."

I'll tell you what's rude. Last New Year I sat between two men at a Northern dinner party.

"Where do you live, then?" said the first. "London," I replied. "Bloody awful place," he said, and ignored me for the rest of the evening. Come the main course, the man sitting on my left broke off from talking about shooting. "What do you do?" he said.

"I'm a hack." "Glad to say I haven't read a newspaper in five years," he said. Now that's rude.

City people, actually, are amazingly polite in the main: they deal with the stress of sharing their space with 10 million others only by being so. The people who create problems are the yokels who come up here and never think about the basic manners you need to get by.

If you don't believe me, try getting through the south side of the Circle Line during the Chelsea Flower Show. Suddenly, the whole city is teeming with old bats.

And they never come singly: they come in pairs or threes, and they always dodder abreast, handbags clutched to their sides, checking their purses every time a black person passes and stopping on the narrowest bits of the pavement to consult the A-Z. In the tube, they stand four-square in front of the gates so that no one else can get past and then start looking in their handbags for their tickets.

I can't help it. There's something about them that brings out the nutter in me. Each time some idiot in a Liberty lawn dress tries to shove her way on a train while the passengers are trying to unload, I get an almost uncontrollable urge to place a hand firmly on her chest and hold her there.

Cities require concerted politeness, watchfulness and way-giving if they're going to be civilised. These troublemakers should stay at home and shop from catalogues.