Ingredients
Cook the fish in the milk, drain, saving the milk, and flake. Make a white sauce with the margarine, flour and cooled milk. Mix the fish into the sauce and season well. Place the mixture in an oven proof dish deep enough to allow the potatoes to be spooned onto the top of fish to cover it completely. Smooth the topping with a fork making as good seal round the edges as possible. Bake at 400 F for 1/2 -3/4 hour to brown the top and ensure the pie is piping hot right through.
Serve with peas and 'red sauce' aka 'dragons blood' aka tomato ketchup.