Lionel Barber is former editor of the Financial Times. He is author of "The Powerful and the Damned: Private Diaries in Turbulent Times."

The building that includes the headquarters of defunct Greensill Bank, a subsidiary of Greensill Capital, in Bremen, pictured on Mar. 23: Lex Greensill's startup was based on an old idea. © Getty Images
Lionel Barber is former editor of the Financial Times. He is author of "The Powerful and the Damned: Private Diaries in Turbulent Times."