Heat a pan and add the oil, then stir in the onion, garlic and celery and cook for about 5 minutes until softened but not coloured, stirring occasionally. Pour in the wine and allow to bubble away, then add the bay leaf, tomato puree, tomatoes, oregano, sugar and season to taste. At this stage you could also add cooked pancetta or chilli flakes etc as desired.
Bring the sauce to a simmer, then simmer gently for about 30 minutes, stirring occasionally, until the sauce is well reduced and thickened. Remove from the heat and leave to cool a little.
When the sauce has cooled, discard the bay leaf and divide between plastic containers. It will keep for a few days in the fridge or is easily frozen.