At his peak, in Middlin’ Middle Age :-).
Traditionally-trained actors from those days had such magnificant diction and resonance. So many of today’s film stars don’t enunciate as well as James.
My favorite example is the Alastair Sim version of Scrooge . . . every actor in the thing is a genius, even Tiny Tim (a wretched part, hard to do well in without being sloppy sentimental) and the little chambermaid who takes Scrooge's coat at his nephew's house on Christmas Day. Sim of course is a master of his trade . . . what an actor!