Much like Boris' clown act, it's an affectation, he doesn't really believe this crap, it's all an act.
Boris' pretend pigeon French act is just that, my daughter was watching him a while back doing it and said if his French was as bumbling as he pretends, he wouldn't have understood the rather nuanced thing that was said to him and certainly wouldn't have even been able to respond in the manner he supposedly attempted. She said he understood perfectly what was said to him and so much so, he gave the response in a less than perfect way throwing in lots in ums and ers and deliberately mispronouncing words slightly but, it was the correct way to respond and only someone with near perfect French would have been able to do it. He spent a good number of his childhood years in school in Belgium, he's pretty fluent
And (no comma) it's exactly the same with Lord Snooty, it's all an act, he really doesn't care. He's more interested in earning vast amounts of money from his funds than any real desire to see a return to Imperial measurements, unless it's to maintain his ludicrously superior air.