Place the ham hock in a large pan, cover with water, and bring to the boil. Reduce the heat, cover the pan, and simmer the ham for one and a half hours.
Rinse the beans, snap off the ends, and place in the pan with the ham. Cook over medium heat for fifteen minutes. Peel and quarter the potatoes, and add them. Continue to cook for a further 20-25 minutes or until the potatoes are tender.
Remove the ham hock, cut off the meat, and chop finely. Place the vegetables in a serving bowl, cover with one cup cooking liquid, and the chopped (or minced) ham. Season to taste and serve immediately with a cruet of vinegar to sprinkle over the vegetables if desired.