Lancashire Hotpot

Cut lamb into 1 inch pieces removing any excess fat. Coat the pieces very well with seasoned flour. Heat up a couple of tablespoons of oil in a frying pan and brown the lamb (at the end soak up any oil with some of the flour). Remove the lamb and put aside. Fry onions in a little oil and butter together with celery. After about 5 minutes once the onion is soft add the lamb back into the mixture. Cook for another couple of minutes. Butter up a casserole ( I prefer a flat one so that you can get more potatoes on the top!). Layer the mixture in the casserole with sliced carrots and sliced leek. Add lamb stock to level just short of covering the mix. Season well. Put a layer of overlapping potato slices on top. Add a few liberal dashes of Worcestershire sauce. Put a dab of butter on the potatoes. Cover and cook for 1 hour and 15 minutes at 180 degrees Celsius. Remove the cover and cook for another 45 minutes so that the potato starts to brown.