Add olive oil to a large frying pan and over a low/medium heat add the mince, onion and carrot and stir until the beef is browned and the vegetables are softened.
3.
Add the bay leaves and thyme and stir through for a minute or so.
4.
Stir in the Worcestershire sauce, tomato paste, chopped tomatoes and stock, and cover and simmer for 30 minutes. Season to taste.
5.
Boil the prepared potatoes until soft. Drain and then mash them adding the butter and milk until you have a nice smooth, not too stiff, mix. Season to taste.
6.
Pour the mince mixture into a large casserole dish and cover with the mashed potatoes.
7.
Bake in the oven for 30 minutes or until golden brown.