The worst by a country mile is Tommy Docherty. I hated the man and what he did to the club. Jewell next and then Davies, simply because he is a horrible, odious, little, sad man.
Best, Cox, Smith and Clough for the great work he did in stabilising the club. Sadly his on field success was not that great though. McClaren could have been up there I guess if he had not shot himself in the foot with his off field antics and disloyalty. He had the foundation of a half decent team, which has now been systematically destroyed.
When it comes to the worst.......MM as owner has to take an award for the way he goes about things with his big stick.