Winston Churchill opposed the Munich Pact because he viewed it as an appeasement to Hitler that would lead to a Nazi invasion of Czechoslovakia and eventual chaos throughout Europe. He proclaimed that the Munich Pact was shameful, dishonorable and a "defeat without a war."
In early 1938, Hitler demanded that Czechoslovakia relinquish the ethnically German Sudetenland to Germany. If Czechoslovakia did not comply, he was ready to invade. Neville Chamberlain, the prime minister of England, met with Hitler to negotiate but could not come to an agreement. In September 1938, the leaders of Germany, Italy, France and England met together and signed an agreement ceding the Sudetenland to Germany without Czechoslovakia's consent. Czechoslovakia, as an ally of France and England, felt it had been betrayed. Germany marched into the Sudetenland the next day. In March 1939, Germany invaded the rest of Czechoslovakia. On Sept. 3, 1939, after the German invasion of Poland, England declared war on Germany.
At the time of the Munich Pact, Churchill had been on a hiatus from government service for several years. After war was declared, he was appointed First Lord of the Admiralty and a member of the War Cabinet. As Hitler invaded country after country in Europe, Chamberlain proved inadequate as a wartime prime minister, and in May 1940, he lost a vote of confidence in the House of Commons. Soon afterwards, Churchill was appointed prime minister on the recommendation of Chamberlain and other government leaders.