1. Prepare and shred the cabbage finely and dice the ham.
2. Put the cabbage, ham, fat, half the stock, and the vinegar in a heavy based pan.
3. Cover, and cook .over gentle heat, stirring from time to time, for 1 1/2 hours.
4. Add the rest of the stock and the sugar and seasoning.
5. Increase the heat and cook for about another 15 minutes, stirring frequently, until almost all the liquid has evaporated.
6. Serve at once.