Nearing pensioning age, Mr. Faulkner's erratic behaviour was excused and explained by other teachers with a roll of their eyes and a long-since-stopped-caring 'It's his last year'. He taught metalwork.
Whereas once we would have to provoke him into sharing his war-time heroics as a parachutist / frogman / desert fox / commando / codebreaker / astro-soldier to avoid working, it eventually dawned on us that he wouldn't give a toss if we just sat there and did our own things for an hour.
After a whole year of learning no metalwork skills at all, and practical assessments looming, a more attentive pupil recalled that we had, at some point, been told to make a trowel. Another child had actually bothered to make one, so those of us who cared about getting a mark dutifully presented this one trowel, in turn, to Mr. Faulkner. He returned the compliment by dutifully giving us all a completely different mark for it.
He also set a written exam which we had no hope of passing but during which I did discover that, apparently, there is a kind of file called a 'bastard' - the only piece of hard metalwork information that I picked up in the whole year. And he probably made that up to take the piss.