Cut the carrots into thick slices and the onions into wedges. Deseed the bell pepper and cut into chunks. Mix together in a deep baking dish coated with a little oil and roast in a preheated hot oven (Mk 7 - 425°F - 220°C) for 15 minutes. Meanwhile cut the chipolatas into 2" (5cm) lengths and quickly brown them in a frying pan with a little oil. Add the chipolatas to the baking dish and roast for a further 10 minutes.
Drain the beans. Reduce the oven to Mk 6 (400°F - 200°C), tip in the tomatoes and beans, then stir in the stock. Cook for another 35 minutes. Stir in the mustard and peas and return to the oven for the last 5 minutes. Rest for 10 minutess, then serve with potatoes, pasta or rice.