Heat the oil in a flameproof casserole dish. Sizzle the sausages in the pan until brown on all sides, then lift onto a plate and leave to cool. If you’re using chipolatas, cut them into shorter pieces. In the same pan, sizzle the pancetta for 5-8 mins until starting to brown. Scatter the onions over the pancetta and cook until soft, then add the garlic and cook for 1 min longer.

Add the tomato purée and sugar, then pour over the vinegar and chopped tomatoes and use about 100ml of water to rinse out the cans and add that as well. Stir through the beans and sausages, then simmer everything for 20 mins. When the sauce is nice and thick, stir through the sage, simmer for a few minutes more and serve. The beans can be made up to three days ahead, chilled and reheated.