Mercenaries are sometimes described as "the world's second oldest profession." But how do they operate today? Can mercenary armies topple dictatorships? Why did one mercenary plot get duped by a Congolese con artist who invented a fake rebel group? Should we pay ex-special forces soldiers to do our dirty work? We'll answer those questions as we speak to Simon Mann, a founding member of Executive Outcomes and a mercenary mastermind of the botched Wonga Coup plot. ----   Power Corrupts is written and narrated by Brian Klaas. The executive producer and sound editor is George McDonagh.