When you start a bus tour, it's traditional for the guide to boast a little about the city you're about to see.
Anti-corruption campaigner Roman Borisovich does not run a traditional tour of London.
"Ladies and gentlemen, I welcome you onboard the Kleptocracy Tour," he announces through the PA system, as soon as we are seated. "As a result of these tours, we have firmly labeled London as the most corrupt place in the world. By square foot, London has attracted a highest-ever concentration of dirty money."