Heat the oil in a heavy-based saucepan over a medium heat and cook the sausages until they are golden brown on all sides. Remove from the pan and set aside.
Add the carrots, onion, mushrooms and garlic to the same saucepan and sweat gently for 3 to 4 minutes, until softened.
Pour in the chopped tomatoes and warmed chicken stock and bring the mixture to the boil. Reduce the heat and sprinkle in the chilli powder, Worcestershire sauce and parsley, then return the sausages to the pan. Season with salt and pepper.
Simmer gently for 10 to 15 minutes, until the vegetables are soft and the sausages are cooked through. Garnish with a few fresh basil leaves and serve immediately with some mashed potatoes.