Drain and rinse the beans and put them in a large saucepan with the bacon, vegetables, garlic, bay leaf and thyme. Season with pepper and cover generously with water. Bring to the boil and boil rapidly for 10 minutes, then reduce the heat, skim any scum from the surface, cover and simmer for 1 hour.
Uncover the pan and continue to simmer for a further hour, stirring occasionally. By thi