Simmer the chopped onion and garlic in half the butter and oil until soft, then cool. Soak the breadcrumbs in the milk, then squeeze out the excess moisture. Heat the grill to high.

Place the lamb in a large bowl. Add the onion and garlic, breadcrumbs, herbs, Worcestershire sauce and egg, and mix well. Season with salt and black pepper.

Divide mixture into 6. Shape each portion into a ball, then roll "in flour and flatten into patties 7.5 cm (3 in) in diameter.

Stretch each bacon slice thinly with the back of a knife to meet round the middle of each patty. If a slice does not reach, use an extra slice. Tie securely with string. Grill the patties for 2 - 3 minutes on each side to seal them.

Heat the remaining butter and oil in a large frying-pan, or 2 smaller pans, and fry the patties slowly on all sides for about 30 minutes until cooked through.

Discard the strings, transfer the patties to a heated serving dish and serve very hot, garnished with watercress.