Preheat the oven to 140°C. Heat oil in a flameproof casserole dish. Add meat and brown on all sides. Transfer to a plate.

Add onions and garlic to dish. Saute until softened. Blend beef stock with mushroom ketchup and Worcestershire sauce. Stir into onion mixture. Add bay leaf, thyme sprig, salt and pepper.

Heat liquid until simmering, then add meat. Cover casserole with foil and a tight fitting lid. Cook very gently for 3 hours, or until meat is tender when tested with a skewer. Put meat on a warmed serving platter. Cover with foil and leave to stand for 10 minutes.

Remove bay leaf and thyme from cooking liquid. Skim fat from surface of liquid. Bring liquid to the boil. Boil until reduced by two-thirds. Slice meat. Pour over gravy.