Sefton Delmer making a propaganda broadcast to Germany from the BBC, 1 November 1941. Photo by Kurt Hutton / Picture Post / Hulton Archive / Getty Images As the Second World War generation leaves us, we ignore the lessons from that conflict at our peril. One is why so many are susceptible to demagogues and their dark propaganda. We once liked to believe the phenomenon belonged to the distant 1930s but now realise it is on a repeat loop – even in countries such as Britain and the US that used to consider themselves immune. Peter Pomerantsev’s timely book draws...