Aged eight, Thomas Graumann excitedly boarded a train in Prague, Czechoslovakia, to embark on what he believed was a three-month holiday. "Go to Britain, learn English, and when the Germans leave, you can come home again," his mother assured him. Thomas carried two suitcases and a bag of food. At the time he knew his country had been taken over by the Germans and now was under Nazi control. That was the last he would...