In fact, she does stay in three nights a week on her own when her husband, Michael Wynn-Jones, the publisher of Sainsbury's magazine, is in London, and she tends to not cook at all. "Maybe I'll do cheese on toast," she says, "with Branston pickle. But," she says, taking my arm in a conspiratorial fashion, "I've got to write a piece for Sainsbury's magazine tonight on watercress so I'm going to try something fun with that! Can't think what, though."