What I learned about capitalism from running a stall on Portobello market

Bargains were snatched from the shoppers who needed them in order to make bigger profits from people with fatter wallets. It was the trickle-up effect at work - much like our system now

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.