Answer:
To warn Chamberlain that the war is inevitable.
Step-by-step explanation:
In 1938 British Prime Minister Chamberlain signed the Munich Agreement with Adolf Hitler according to which Germany gained the right to annex part of Czechoslovakia.
Churchill criticized the British Prime Minister, accusing him that by signing an agreement with Hitler he showed weakness. According to Churchill, Czechoslovakia was sacrificed by the great powers only so they could preserve good relations with Germany.
Churchill delivered his famous A Total and Unmitigated Defeat speech in front of the House of Commons, stressing out why the Munich Agreement is bad for Britain. He believed that the war with Germany was inevitable, and that is why it was necessary to show that there is no place for withdrawal.