Football managers operate in a trade which is prone to immediate judgement in a society where perception trumps reality. Dynastic managers are few and far between. They are disposable commodities in a ruthless industry which hires and fires with impunity. In the 2018-19 season, 44 of the 92 managers in top four leagues lost their job. The merry-go-round was in full swing in the non-leagues, too. The Gaffer, the latest in BT Sport’s award-winning series of feature-length documentaries, offers ...