I noticed that he says ‘an historic honor’ at 2:43. I know it’s silly to point this out, but I didn’t expect this from a native English speaker, and presumably an intelligent one given his credentials. They need to run his speeches through autocorrect ¯\_(ツ)_/¯
I’m not questioning his abilities as the prime minister, but I’m just slightly disappointed. As citizens, we should always criticize people in power. If they’re intelligent than the average, criticize them even more fiercely! Anyhoo, I’ll brace for the downvotes lol.
You’re tripping yourself up on the difference between British English and American English. Canadian English is tolerant of both forms.
Oxford, where he wrote his thesis, would require ‘an’ before ‘historic’. When Governor of Bank of England, he would have had to have been careful to use British English.
If you’re a Canadian using American spelling and grammar checkers to define your language, you might wish to reconsider that. MS Word does have Canadian and UK English options.