Heat the oil in a frying pan over a medium heat and fry the onion for 6-8 mins until soft and beginning to brown. Add the garlic and anchovies and cook for 1 min more before scattering in the chilli, if using, and the oregano. Cook for 30 seconds, then tip into the slow cooker.

Pour in the can of tomatoes, then swill out the can using 1 tbsp water and pour this into the slow cooker. Add the squid, capers and olives. Pour in the white wine and give everything a good stir. Cook on high for 3 hrs until the sauce has thickened a little (it will be soup-like). Serve in bowls with the chopped parsley scattered over and some crusty bread for dunking.