For years, the City of London's bankers and lawyers have worked as butlers, metaphorically speaking, for oligarchs from around the globe, transforming them from corrupt thieves into British aristocracy, author Oliver Bullough said during a book launch event.

I used the occasion of Bullough’s book launch to write about how the U.K. turned Dmytro Firtash, a Ukrainian gas tycoon who made a fortune by working with Russia’s state-owned Gazprom, into quasi-aristocracy, in part by selling him a disused tube station in London.