I have recently been watching the BBC series Civilisation, produced and narrated by Kenneth Clark in 1969; and some of his pronunciation is quite surprising.
He has a raised /æ/ vowel (the TRAP vowel), and he also has a voiceless sound at the start of 'what' and 'which' (so 'which; and 'witch' would be distinguished); but both these are expected for an RP speaker of his generation.
However, some other words are more unexpected, and I wonder if they are idiosyncrasies of his pronunciation. For example, he pronounces 'capitalism' with stress on the second syllable: 'caPITalism', which sounds very strange. (Listen here).
I've just checked in the Longman Pronunciation Dictionary (3rd ed., 2008, p. 123), and this variant is listed as one possibility, so maybe Kenneth Clark was not so idiosyncratic after all. But I've never heard it as 'caPITalism' before, and it took me a moment to understand it.
