Who was prime minister of England during wwll?

At first it was Sir Neville Chamberlain- he had been in office since '37 and had signed a peace deal with Hitler at the Munich Summit Meeting in 1938, at which Hitler promised not to annexe any further countries within the Third Reich after his invasion of Austria and Czechoslovakia. Chamberlain was desperate to avoid another European war, remembering all to clearly the apocalypse of WW1 which saw millions of deaths. But Hitler broke his promise and invaded Poland at the beginning of September 1939, forcing Chamberlain to declare war on Germany on 3rd Septmeber.

He sent a massive British Expeditionary Force into France to help the French armed forces keep the Nazi's from occupying France, but the disastrous British retreat from Dunkirk lead to his resignation in February 1940, to be replaced by Winston Churchill.

Churchill headed a coalition government until the end of the war in Europe in May 1945, but very soon afterwards a General Election was called, which saw a Labour government under Clement Attlee elected. Attlee was thus Prime Minister when the war ended in the Far East, in the August of '45.