Britain in World War II By fthis Sep 29, 1938 Munich Pact Sep 29, 1938 The Munich Pact is signed Sep 3, 1939 Germany Invades Poland Sep 3, 1939 Britain declares war on Germany Sep 3, 1939 Germany Invades Poland Sep 3, 1939 Britain Declareswar on Germany May 10, 1940 Winston Churchill becomes Prime Minister of Britain Period: May 27, 1940 to Jun 4, 1940 The Evacuation of British troops at Dunkirk Period: Jul 10, 1940 to Oct 31, 1940 Battle of Britain Period: Jul 10, 1940 to Oct 31, 1940 Battle of Britain Jul 27, 1942 Battle of El Alamein Nov 5, 1942 The battle of El Alamien Jun 6, 1944 Invasion of Normandy by Allied forces Jun 6, 1944 Invasion of Normandy May 7, 1945 Germany Surrenders to Allied forces May 7, 1945 Germany Surrenders to the Allies Feb 10, 1947 Paris Peace Conference Feb 10, 1947 Paris Peace Conference