In a large frying pan, brown mince over medium heat until no longer pink; cut up any remaining chunks of beef and reserve.
In a large saucepan, combine whole tomatoes and paste; mash until smooth. Cover and heat on low.
In a large frying pan over medium heat, quickly sear onion and celery until transparent; add to spaghetti sauce in saucepan. In same frying pan, saute capsicums and mushrooms for a few minutes, but do not allow them to become soft; add to sauce.
Add Italian herbs, dried red pepper flakes, bay leaves, basil and garlic to sauce; add mince then mix. Remove cover, simmer over low heat and continue to simmer all day, stirring occasionally.
Bring a large saucepan of lightly salted water to a boil. Add spaghetti and cook for 8 to 10 minutes or until al dente; drain. Add sauce to pasta; serve.