I once had a stall in the Portobello Road market, when it still had a cheap, rubbishy end where you could find thrilling bargains. My stall was at this fascinating, vibrant end, between a book stall and a bric-a-brac stall, on a pavement forecourt facing the public lavatories.

Every Saturday, the bookseller, who also sold cinema ephemera, would leave me in charge and go down to the swanky part of the market, which was crammed with tourists. There he would find his own stock, which dealers had snapped up from his stall early in the morning, to sell at a staggering profit on their own stalls, 10 minutes’ walk away.

This was one of my lessons in capitalism – the trickle-up effect. The bargains were snatched away from the shoppers who loved and needed them, by the ones who didn’t, to be distributed, at a profit, via flashier stalls, to people with fatter wallets, who couldn’t be fagged to walk up the road and take a little trouble searching, or who didn’t want to walk among the riff-raff, or the more vulgar stall-holders. But they needn’t have worried. I only remember one really offensive trader. We called her Mrs Fuck-Pig because that’s what she would shout at any shopper who slightly displeased her.

The bookseller didn’t mind the profiteers. He was just curious about them, and his real love was for his stock. He loved searching for it, storing it, wondering at it, chatting about it and selling it at a reasonable price. But I found that I couldn’t always get even a reasonable price for my tailors’ trimmings. I didn’t need much profit. My stock had landed in my lap, bought accidently at auction by my father. But I still didn’t want to throw it away.

Here came the second lesson. As it was nearly Christmas, the bric-a-brac lady had found some logs, stuck holly in them and sprayed them silver. They weren’t selling. So what did she do? Doubled the price. They sold like hot cakes. “If they’re too cheap,” she said, “‘people think they’re rubbish, but if they’re expensive, people think they must be good quality, so they cough up.” It worked a treat. I raised my prices, and my mother-of-pearl buttons, bakelite and enamel clasps, herringbone and devoré fabrics and other treasures from the 30s and 40s, sold like mad.

The trouble is that the swanky end has now spread like a deadening plague because councils don’t like cheap-end markets. They prefer what a developer once determined Covent Garden should be: “a Selfridges without a roof”, and that’s what our street markets are all becoming, like our housing and whole system: nothing much affordable is allowed to circulate at the bottom, everything sucked up to the top. Third lesson: time for a new-style economics. Quickly please.