Preheat the oven to 200C (400F / gas mark 6).
Boil the potatoes for 15-18 minutes until completely soft, then drain and mash with the milk and butter until smooth.
Meanwhile, brown the turkey mince in a pan, breaking it up as it cooks.
Add the diced carrots and stock to the mince, and simmer for 12-15 minutes until the carrots are very soft and the liquid has reduced slightly. Stir in Worcestershire sauce if using.
Spoon the mince mixture into small ramekins and top with the mashed potato.
Bake for 12-15 minutes until lightly golden on top.