Why did Chamberlain's policy of appeasement fail to prevent the outbreak of war in 1939?

Appeasement is the name often given to British foreign policy in the year 1919 to 1939, but it is particularly associated with Neville Chamberlain who became Prime Minister in 1937. Chamberlain believed in talking an active role in solving Hitler's grievances. He felt that Germany had good reason to be upset at many of the terms of the Treaty of Versailles. What he wanted to do was to find out exactly what Hitler wanted and showed him that reasonable claims could be met by negotiation instead of by force. In this way, the problems of Versailles would be solved, Germany would be satisfied and there would be no war. Chamberlain was aware of the risks of appeasement.

The risk were that it depended on Hitler's aims being reasonable and limited to righting the wrongs of the Treaty of Versailles. It meant trusting Hitler and believing that he was telling the truth. After 1937 France supported appeasement because of the…