Split the sausage casing lengthways; peel off the casing and discard (or leave the sausages intact and squeeze the meat from the casings). Roll the sausage mixture into walnut-sized balls.

Heat the oil in a large saucepan over medium to high heat. Cook the meatballs for 5 minutes, shaking the pan occasionally, until browned all over. Remove from the pan with a slotted spoon.

Add the onion, garlic and celery to the same pan; season. Cook, stirring, for 5 minutes or until softened.

Stir in the stock and tomatoes; bring to the boil. Cook for 8 minutes or until reduced slightly. Return the meatballs to the pan with the beans, cook for 1 minute or until heated through.

Just before serving, add the Swiss chard; stir until wilted. Sprinkle with basil leaves. Serve with crusty bread.