Begin by heating some dripping into a large flameproof casserole.Trim any excess fat from the meat, then season the pieces and fry them in the hot fat until brown on all sides. Now sprinkle in the flour and, keeping the heat fairly low, stir it around to soak up the juices. Next add the hot water, tomato purée, crushed garlic and thyme. Then bring everything gently to simmering point, giving it a stir now and then. Put the lid on and cook very gently for 45 minutes.While that’s happening, using a little more dripping, fry the prepared onions, turnips and carrots. When the 45 minutes are up, add these vegetables to the casserole, along with the scraped potatoes, and bring to simmering point again. Add the sugar, cover and continue to simmer gently for a further 45 minutes.