Wash and slice the leek. Heat a medium-sized pan and add the oil then cook the leek for about 7 minutes until it has softened and then pour in the passata and 200ml of water.
Add the tomato puree, Worcestershire sauce, sugar, vinegar and paprika if using. Season with salt and pepper and mix well and bring to the boil, then reduce the heat and simmer for 30 minutes over a low heat before adding the beans. Leave them to cook for another 10 minutes before serving them with toast or as a side dish with a full cooked breakfast.
