Tip - MASTERCLASSES; DRAWING; Just pick up a pencil and start looking

I'M SITTING in the garden of the Chelsea Arts Club, sharing a glass or two (as Chelsea folk do) with my art teacher, Stan Smith. We're talking about the agonising self-consciousness of sketching in public, when the painter Dennis Gilbert joins us: "I've had the most humiliating experience," he says. "I was in St James's Park, sketching a deck chair under a tree, when a woman came up to see what I was doing. She took one look, went over to the chair, picked it up and walked off with it."