Place the bacon joint in a large bowl and cover with cold water. Leave to soak for at least 3 hours, or overnight if it is very salty.

Drain the bacon and place it in a large saucepan. Cover with fresh cold water. Bring to the boil, then cover and simmer for 1 - 1 1/2 hours, depending on size, until tender. Cover the raisins with 275 ml (10 fl oz) lukewarm water and leave to soak for about 1 hour.

Heat the oven to 180°C (350°F) gas 4. Drain the raisins and reserve the soaking liquid.

When the bacon is cooked, drain it well. When it is cool enough to handle, remove and discard the skin. Using a sharp knife, score the fat in a diamond pattern. Stud the diamonds with cloves.

Combine the mustard with the brown sugar, and spread this evenly over the scored fat of the bacon. Place the joint in a roasting tin, fat side up. Pour the lager into the pan and baste the lean sides of the joint only. Bake in the oven for 25—35 minutes, basting the lean meat of the joint occasionally with the pan juices.

Transfer the bacon to a heated serving dish. Skim the tin juices of excess fat if necessary. Place the roasting tin over high heat and boil it to reduce the juices by half. Add the reserved raisin soaking liquid to the roasting tin and bring to the boil, stirring and scraping the bottom and sides of the pan with a wooden spoon.

Dissolve the cornflour in 30 ml (2 tbsp) of cold water and stir into the liquid in the roasting pan. Bring to the boil, stirring constantly, and simmer until the sauce is thick and smooth. Add the wine vinegar and raisins and mix well. Pour into a heated sauce-boat and serve the sauce with the bacon.