1. Peel and finely dice the onion.
2. Peel and finely chop the garlic.
3. Wash, peel and rewash the carrot and cut into finger shape.
4. Wash the celery and cut into finger shapes.
5. Cut off any fat from the bacon rashers.
6. Wash the herbs.
7. Tie the following into two small bundles-celery, carrot, parsley stalks, basil, thyme sprigs, bay leaves and bacon rashers.
8. Weigh all the other ingredients.
9. Heat the oil in a large heavy-based saucepan.
10. Add the garlic and onions and sweat over a gentle heat without color for 3 to 4 minutes.
11. Add the chopped tomatoes and mix in the tomato purée.
12. Add the sugar and the small bundles of herbs and bacon.
13. Bring to the boil, turn down the heat and simmer the tomato sauce gently for about 25 minutes.
14. Remove the bundles of herbs and bacon.
15. Season the tomato sauce to taste and use as required.