Top Level Actors In Hindsight: Leo McKern.

He was a UK actor of fine skills. I doubt that would be denied.

For those Americans old enough to know PBS before it went to total political shit, he was Rumpole Of The Bailey.
One episode plot has a rather young nerdy teacher who is seduced by his female student, who is (if I still remember) egged on by her same-aged boyfriend for the purpose of blackmail.

Things get blurry, and I don't get invested enough to research when I know I am more or less correct. The teacher gets busted, but Rumpole rightly later says some wise and sympathetic words toward the teacher.

The same actor is the captain in the early scenes of the film Blue Lagoon.

I definitely like Leo McKern.