Finely chop the garlic and put it in a pan with the olive oil. Simmer for three minutes on a low heat.
Quarter the tomatoes and roughly chop the pepper and when the garlic is done, add to the pan. Simmer gently for 1 minute
Add the water and cornflour, stirring constantly to get a thickened sauce. Then add the pesto, chilli sauce and the tomato purée, stir on a low heat for around 10 minutes.
Finally, add the sugar, salt and pepper to taste to judge acidity and leave for 2 minutes so that the tomatoes and peppers have fully softened. Present with torn basil leaves and some crusty bread.