Winston Churchill, who would become the British prime minister in 1940 described which agreement as a 'defeat without a war'?

Winston Churchill refers to the Munich Agreement of 1938, signed by his predecessor, British PM Neville Chamberlain and France, by which Great Britain and France accepted the annexation of the Sudetenland by Nazi Germany in exchange for a promise of no more expansionist moves. It was an attempt to preserve peace, though it left Czechoslovakia alone to defend herself. The accord is seen as useless appeasement of Adolf Hitler and of failed diplomacy. Anywway, war happened one year later.