Put all of the slow cook ingredients into the slow cooker and cook for 6 hours on HIGH or 8 hours on LOW.
Add the Worcestershire sauce and fresh basil.
If you want to serve with spaghetti, boil the spaghetti for 2-3 minutes less than the usual cooking time. Drain and add to the bolognese sauce, with a splash or two of reserved cooking water. Stir well and allow the pasta to absorb the sauce a little and soften.