Nazi Germany invaded Poland on September 1, 1939. On September 3, 1939, two days later, Britain and France declared war on Nazi Germany. Polish resistance to the invaders collapsed in days but events in Western Europe appeared stable.

The seven months after the declaration became known as the "Phoney War." This was because conditions at home were not greatly changed no physical attack was made on Germany to back up the declaration. However, the atmosphere had changed as people began to act more cautiously in the everyday life. Communication between Britain and Germany became difficult and those people who had relatives and friends in the Third Reich, found it difficult to contact them.

The Allied governments made plans for an escalation of war. Rearmament and conscription had already started in March and April 1939 in Britain.

Immediately after the declaration of war the British Prime Minister Neville Chamberlain had formed a War Cabinet. Significantly it included Winston Churchill in the post of First Lord of the Admiralty. Churchill had first hand experience of war and had served in the British government during the First World War.

For civilians in Britain, evacuation plans were made and some even began to move from cities. Rationing began at the start of 1940.

In April 1940 Nazi Germany invaded Denmark and Norway. Both countries were rapidly defeated and occupied. The Nazis quickly moved towards the rest of Western Europe and invaded the Netherlands, Belgium and France. The "Phoney War" was over for Britain and her allies.