I'm not inviting nominations here. I have but one candidate for this title, a man whose personal qualities and actions during his period of tenure put him, I would argue, clear ahead of the field as the worst Old Trafford boss of all time.
Ladies and gentlemen, I give you: Sir Alex Ferguson.
Now, let's not be simplistic about this. The worth of a football manager - who, let's not forget, carries the responsibility for how his club is perceived by friends and foes alike across the globe - cannot be measured by a mere count-up of baubles won. What is the standing of the football club when he arrives? How will he leave that club when he finally clears his office?
In Ferguson's case, the answer is glaringly obvious. He has presided over the most horrendous degradation of a football club's standing and image that I can bring to mind. Manchester United, thanks almost entirely to the stewardship of Sir Matt Busby, was once upon a time the football club most closely associated with honour, dignity and The Way Things Should Be Done. Only Arsenal, and later Liverpool would come anywhere close to matching the standards set by Sir Matt.
Busby did not have it easy. He arrived at a bombed-out Old Trafford in 1945, with a history as a Manchester City and Liverpool star behind him. This was hardly calculated to endear him to the devotees on the Stretford End. He also had to contend with the slightly shady influence of the ruling Edwards family over the club, and of course he suffered hideous personal injuries in the Munich air disaster, as well as losing the core of his second great team. Against this backdrop, he created a club that was known as 'everyone's second favourite team', and beloved of their own massive following.
Looking back, it is sad to see how the legacy of Sir Matt Busby has been squandered. Manchester United these days are perhaps the most hated brand - I use the word advisedly - in the sporting world. Given the amount of trophies won under Ferguson's ruthless management, it would be easy to ascribe this to envy. But there have been successful, dominant clubs before, and none have attracted quite the same level of opprobrium.
The Ferguson Factor is the difference here. Busby and Ferguson were both at the helm long enough to be completely identifiable with the club they represented. Busby stood for dignity and respect, Ferguson stands for arrogance and intimidation. His most recent rant is symptomatic of this. A playground taunt whereby he is manager of the most famous club in the world, and his opposite number is at "a wee club in the north-east".
The small-mindedness of such language is mind-boggling in such a major sporting figure, and Ferguson has plenty of form in this regard. His club suffers more with every such outburst, and for all their fans claim they don't care as long as the trophies roll in, I beg leave to doubt this. We all need to be loved, respected, admired. Manchester United has little of this now, outside of its own rabid support, but there was a time when the club was a byword for affection and respect among football lovers everywhere. This is the scale of the downfall; this is the measure of the negative effect of Ferguson's reign.
Sir Alex Ferguson - the original knight you wouldn't send a dog out on. J'accuse.
Follow Rob Atkinson on Twitter: www.twitter.com/RobofLeeds