Heat the olive oil in a deep flameproof casserole dish. Add the Cumberland sausages and fry for between 5-10 minutes until caramelised and browned.
Add the onion, leek and peppers to the casserole and fry for a few minutes, or until softened.
Make up 1 litre of stock with the cube and pour into the dish. Stir in the country vegetable mixture, season and then cover with a lid.
Simmer for 30-40 minutes until tender, then serve.
Cook's tip: Some crusty bread would make a great accompaniment, so that you can soak up all the lovely liquid from the stew!