Prepare a sheet of foil large enough to wrap around the meat completely

Peel and slice 1 or 2 of the garlic cloves. Make small cuts in the underside of the meat and insert the slices of garlic into this. Put the meat onto the foil with the bay leaves underneath.

In a small bowl, mix the margarine thoroughly with the remaining ingredients. Spread this mixture over the upper surface of the meat, using a wetted palette knife.

Loosely wrap the foil around the joint of meat, place in a roasting tin and roast in a preheated oven, 200°C/400°F/Gas Mark 6, for about 1 3/4 hours.

Unwrap the foil and baste the joint with the melted fat that has collected in the base of the tin.

Continue roasting; uncovered, for a further 30 minutes, until the crust is brown and crisp.