United Kingdom declaration of war on Germany (1939) significant event invasion of Poland
The United Kingdom declared war on Germany on 3 September 1939, two days after Germany invaded Poland. France also declared war on Germany later the same day.
The state of war was announced to the British public in an 11 AM radio broadcast by the prime minister Neville Chamberlain.This morning, the British ambassador in Berlin handed the German government a final note stating that unless we heard from them by 11 o'clock that they were prepared at once to withdraw their troops from Poland, a state of war would exist between us. I have to tell you now that no such undertaking has been received, and that consequently this country is at war with Germany.After the declaration of war
The Royal Navy initiated a naval blockade of Germany on 4 September.
Although Britain and France honoured these guarantees by declaring war two days after Germany's invasion of Poland on 1 September 1939, and the dominions of the British Empire quickly followed suit, so little practical assistance was given to Poland, which was soon defeated, that in its early stages the war declared by Britain and France was described as a "Phoney War".
Further, neither the British Empire nor the French ever declared war upon the Soviet Union, which invaded Poland on 17 September 1939 (16 days after Nazi Germany invaded from the West). The Polish ambassador in London, Edward Bernard Raczyński, contacted the British Foreign Office to point out that clause 1(b) of the agreement, which concerned an "aggression by a European power" on Poland, should apply to the Soviet invasion. Foreign Secretary Lord Halifax responded that the obligation of British Government towards Poland arising out of the Anglo-Polish Agreement was restricted to Germany, according to the first clause of the secret protocol. The Soviet Union held sway over the former Polish territory at the war's conclusion, having become a part of the Allies in the course of World War II. At the insistence of Joseph Stalin, the post-war Yalta Conference in 1945 sanctioned the formation of a new provisional pro-Communist coalition government in Moscow, which ignored the Polish government-in-exile based in London.