Heat oil in a large flameproof casserole or non-stick deep frying pan over medium-high heat. Add meat in batches and brown on all sides, about 5 minutes per batch. Place in a bowl.
Add the potato, carrot, onion, leek and turnip to pan. Cook for 10 minutes; stir occasionally. Stir in flour. Add water, bay leaf, rosemary, salt and pepper. Bring to the boil. Reduce heat. Add meat. Simmer, uncovered, until meat is tender, 50 to 60 minutes. Add peas. Simmer 5 minutes; serve.