He is Professor of Law at University College London and a barrister and arbitrator at Matrix Chambers. He is the author of Lawless World (2005) and Torture Team (2008 and contributes to the New York Review of Books, Vanity Fair, the Financial Times and The Guardian. His latest book is East West Street: On the Origins of Crimes Against Humanity and Genocide, winner of the 2016 Baillie Gifford (Samuel Johnson) Prize and 2017 British Book Awards Non-Fiction Book of the Year. It is accompanied by a BBC Storyville film, My Nazi Legacy: What Our Fathers Did. He is now writing the sequel.