Alexander Boris de Pfeffel Johnson aka Boris Johnson is not as clumsy as his haircut makes him look to be. The guy keeps fit, doesn't look like Rambo but he is fit with a bit a sticky build. He is intelligent, he survived the muddy waters of politics, affairs and is prime minister. Of course he always knew he is American dual citizen, a person like him does not handle an apartment sale himself, he has handlers and advisors. And he was in a very high income bracket for a while and it's safe to say he fell into a us taxable segment before that sale. He is a showman and this was just the event where the tax bill was too high and he said "no more".