Put the ham in a large bowl and cover with cold water. Soak overnight, then drain. Transfer the ham to a large saucepan and just cover with water. Add the bouquet garni, peppercorns and vegetables. Bring to the boil. Reduce the heat to low and simmer for about 4 1/2 hours (allow about 25 minutes per pound for a fairly large ham, a little more for a smaller one).

Remove the pan from the heat and allow the ham to cool in the liquid.

Preheat the oven to moderate 180°C (Gas Mark4, 350°F).

Combine the sugar, mustard and 50 ml (2 fl oz) (5 cup) of the whisky and set aside.

Remove the ham from the pan and wipe dry with kitchen towels. Cut away the rind then, using the point of a sharp knife, score the fat in a diamond pattern, making cuts through the fat to the meat. Transfer the ham to a rack in a roasting pan. Coat the scored ham with the remaining bourbon. Using a rubber spatula, spread the sugar mixture generously over the ham, push the cloves into the fat and arrange the orange segments over the top and sides, securing them with cocktail sticks.

Put the ham into the oven and roast it, basting occasionally, for 1 hour. Serve at once.