At least when I was in school British actors came out of repertory. Even in New Zealand (in many ways transported Brits) every town had its own amateur repertory society. It was a very natural thing in English society -- or rather, unnatural. It was the eccentric side that was OK expressed on a stage as opposed to real life. In the same way that British carnival was detached from land and at the end of a pier.

To my mind that explains the likes of Monty Python and Prince Charles, otherwise so straight laced, mimicking it.

This British duality produced great actors. And Pop music. And maybe racing car drivers?

Many thanks