The British and their vegetables have always been something of a puzzle. How is it that at flower shows and country fêtes you can marvel at the delicate tints and perfect flesh of rosy carrots, silvery leeks, snow-white cauliflowers, tomatoes glowing with health, green peas in matchless pods, broad beans and lettuces, radishes and cabbages all bursting with freshness and variety, and then find, all too often, in British kitchens, particularly those of restaurants, the saddest sorriest apologies for vegetables that can be seen anywhere in the world.