The Pol Roger Duff Cooper Prize for the best non-fiction published in the UK is awarded to Julian Jackson for France on Trial: The Case of Marshal Pétain (Allen Lane). The book, described by the judges as “asking profound, historical questions about how to act in impossible circumstances”, uses the 1945 trial of Marshal Pétain to explore collusion and its consequences in post-war France.

Pétain, the aged hero of Verdun, was tried for treason by his countrymen for signing the armistice with Nazi Germany and for leading the collaborationist Vichy regime. The guilty verdict may have been a foregone conclusion, but the case was never about one man alone: every level of French officialdom, particularly the deeply compromised justice system, had terrible questions to ask and to answer. Jackson, in paying as much attention to the stances of witnesses, jury, lawyers and judges as to those of the accused, shows what happens when a battered nation, freed from its enemies, is forced to confront its own shame.