Divide the beans into two equal portions. Put one portion of beans into a pan, cover with water and bring to the boil. Lower the heat and simmer for about 1 hour, or until tender. Drain.

Mash the cooked beans lightly with back of a wooden spoon to break them down a little. Mix with half the mint, the breadcrumbs, egg and seasoning.

Use to stuff the cavity of the meat and tie securely. Cook any extra stuffing separately.

Place the meat in a large deep casserole and put the rest of the beans round. Pour over the stock with the remaining mint added. Season, cover and cook in the oven at 150°C (300°F) mark 2 for 3 - 3 1/2 hours until the meat and beans are tender.

Pour off the juices and keep the meat and beans warm. Skim the fat from the juices. Blend the cornflour with cold water and stir into the juices. Bring to the boil, stirring and season.

Serve the lamb with the whole beans and hand the gravy separately.