Throughout his career, Bonnet was widely respected for his intelligence but often inspired great mistrust in others, in part because of his highly secretive methods of working and his preference for verbal as opposed to written instructions. During his time as Foreign Minister, Bonnet was distrusted by the British, Daladier and senior officials in the Quai d'Orsay, all of whom suspected that he was in some way not quite being honest with them. Neville Chamberlain described Bonnet as "clever, but ambitious and an intriguer". Georges Mandel said: "His long nose sniffs danger and responsibility from afar. He will hide under any flat stone to avoid it". The French columnist André Géraud, who wrote under the pen-name Pertinax, stated that Bonnet pursued only the line "of least resistance". Sir Winston Churchill described him as "the quintessence of defeatism". In December 1938, Lord Halifax's private secretary Oliver Harvey referred to Bonnet as "a public danger to his own country and to ours". In December 1939, the British Chief Diplomatic Advisor Robert Vansittart wrote: "As to M. Bonnet he had better trust to time and oblivion rather than to coloured self-defence. He did a lot of really dirty work in 1938... if I ever had to play cards with M. Bonnet again I would always run through the pack first, just to make sure that the joker had been duly removed". And throughout Berlin Diary the author William L. Shirer referred to him as "the insufferable Georges Bonnet".