Probably David Chipperfield or maybe Norman Foster.
Nigel Hawthorne.
Absolutely! Cooke was a pure English gentleman and scholar.
His BBC radio program “Letter from America” was the longest running broadcast in radio history: a weekly report of news and social commentary which ran continuously from the 1930’s until just a week or two before he died.
But, ironically, it was not broadcast in the USA 
Stephen Fry.
James Mason.
Another vote for Patrick MacGee
Geoffrey Palmer
Ken Barrington
James May
Spot on!
I’m going with Jeremy Irons, but I wish I could go with Benedict Cumberbatch, seeing as how his name is “Benedict Cumberbatch.”
Benedict Cumberbatch, Hugh Grant, Colin Firth … that type of guy
Yeah, I think this is correct. RobDog noted the difference as well.
I’m nominating Sir Arthur John Gielgud.
If he’s archetypal, surely he must have a bowler hat and brolly.
You rang, ma’am?
Alistair Cooke probably gets top marks: erudite, refined, courteous, affable, and with that marvelous accent. Just what every Englishman ought to be.
Andy Capp
Lots of great examples here and let me throw one more into the ring
Roger Allam - mainly for the voice but the cut of his jib in “the thick of it” screams “English Gent”
Aleister Crowley.
Roger “Simon Templar” Moore
This.
Thomas Craig, the actor who plays “Inspector Brackenreid” on Murdoch Mysteries.
In this interview at the one-minute mark, Craig is slightly embarrassed at having used a Canadian term instead of a British one, in a way I find comical and endearing.