It is all very well for me and other cookery writers to extol the virtues of buying locally grown vegetables in season, their low cost, their freshness, their ‘appropriateness’ with other seasonal food. Low cost? Not long ago I went into a supermarket in Plymouth to buy, amongst other things, parsnips. I didn’t need many, but the bag came to £3.64. Ah well, supermarkets, I hear you say. Why didn’t I go to a local greengrocer? In fact, Stokes of Bodmin did have parsnips, but I also wanted Jerusalem artichokes, radicchio, Chinese leaves, fennel, kohlrabi, uncooked beetroot, butter nut squash and salsify.