Drain the beans and place in a large pan. Add the onion, garlic, bay leaf, parsley and oil. Cover with cold water and bring to a boil, then simmer, partly covered, checking that the beans are at all times covered with water.
Wash the clams, place in a separate pan with just a little water, cover and cook over a medium heat until the steam opens them up. Remove the empty half shells, drain the stock and leave to cool.
When the beans are practically cooked, add the clams, breadcrumbs, crushed saffron and the cold clam stock. Gently shake the pan to blend the ingredients and continue to cook over a low heat for a further 10 minutes. Season with salt and leave to rest for a few minutes before serving.