Drain the beans, place them in a large flameproof casserole with sufficient water to cover. Bring to the boil and boil rapidly for 10 minutes, then simmer covered for 45 minutes.
Drain the beans and return them to the casserole with the remaining ingredients. Mix thoroughly, season with salt and pepper, cover and bake in the oven at 150C/300F/gas 2 for 4 hours until the beans are tender. Check and stir the beans occasionally during cooking and add a little water if necessary to prevent them from drying out. Taste and adjust the seasoning if necessary before serving.