Put the beans into a large pan, cover with 3 times their volume of water and bring to the boil. Boil for 10 minutes, then lower the heat and simmer until the beans are just soft, about 45 minutes to 1 hour, depending on their age. Season with a little salt in the last 5 minutes of cooking time. Drain the beans and set aside.
Heat the oil in a large heavy pan and fry the sausages,