1 Place the gammon in a large pan with the onion, carrot, leek, cinnamon, peppercorns, coriander seeds and bay leaves. Cover with cold water, bring to a boil then simmer very gently for about 2 1/2 hours, topping up the water if needed during cooking.
2 Remove the meat from the pan and let it cool a little - the cooking liquid can be used as a stock to make soup. Heat the oven to 180ºC (160ºC fan) 375ºF, gas 5.
3 Cut away the skin from the meat leaving an even layer of fat. Score the fat in a criss-cross pattern and stud the fat with the cloves then place in a roasting tin.
4 Place the brown sugar, beer, honey and mustard in a small pan, bring to a boil then pour half over the meat, making sure it is evenly coated. Roast in the oven for 15 minutes then pour the remaining glaze over the meat, baste well and roast for another 30 minutes, basting from time to time.
5 Let the meat cool and serve warm or cold.