In a large pan, heat the oil and fry the onion over a medium heat for 7 minutes. Add the garlic and chilli and cook for 3 minutes more. Add the oregano, cumin, paprika, chilli powder and chipotles. Stir and cook for a few minutes more.
Add the beans, tomatoes, tomato paste and stock. Gently simmer, uncovered, for 30 minutes, stirring every so often to prevent the beans from sticking to