There were a few significant military land actions during this period:

• The Saar Offensive: French troops briefly attack Germany, venturing a few miles across the border in support of Poland, before withdrawing back to their starting positions.
• The Winter War between Finland and the Soviet Union started, in which France and Britain considered launching an offensive to assist Finland, although ultimately these plans came to nothing when the war ended in March.
• The German Invasion of Denmark and Norway in April 1940, resulting in the Allied troops earmarked for Finland being instead sent to aid Norway. After weeks of heavy fighting, the Allies were forced to evacuate their forces, leaving Germany in control of Norway.

At sea, the Battle of the Atlantic was already underway, and several clashes occurred during this period:

• A passenger ship the SS Athenia is sunk by a German submarine on the first day of the war, killing 117 civilian passengers and crew
• The British carrier HMS Courageous also being sunk by the U-29, with the loss of 519 lives on 17 September 1939.
• The sinking of the the aging British battleship Royal Oak at Scapa Flow by the German U-47 on 14 October 1939.
• The scuttling of the Admiral Graf Spee in Montevideo, Uruguay on 17 December 1939, after being pursued and cornered there by a force of British cruisers.
• The dramatic events of the Altmark Incident on 16–17 February 1940, which resulted in the rescue of around 300 British prisoners-of-war.

In the air, both sides conducted small-scale bombing raids and reconnaissance flights.

• As early as the 4 September, the Royal Air Force attempted daylight bombing raids on German warships in Heligoland Bight but they proved to be ineffective and incurred a heavy toll on the attacking Blenheim and Wellington bombers, leading to the daylight operations being abandoned by the RAF heavy bombers.
• The German Luftwaffe began launching raids on Britain from 16^th October 1939, attacking British warships at Rosyth on the Firth of Forth, Scotland, resulting in the loss of several aircraft without any tangible results to show for their efforts.
• The USA was neutral at this point, and President Roosevelt was concerned about casualties from bombing and proposed that no bombing raids be launched that might harm civilians. The British and French – keen to not push German into retaliation which may escalate matter further - henceforth restricted their aircraft to dropping leaflets and carrying out reconnaissance.

It certainly made sense that the troops here – having been likely brought up with relatives who may have experiences the horrors of the First World War – might well have absorbed the fears of such a massive, destructive conflict ever happening again. So, when they then found themselves facing the sons and grandsons of their nation’s old adversary, situated only a few hundred yards away, across barbed wire and fortifications, it is little wonder that an attitude of ‘live and let live’ appears to have been adopted.

Meanwhile, the Germans kept themselves busy, indulging in racing games and assisting the local population, in return for food and drink, drinking mulled wine in local inns, their morale lifted by their army’s victory in Poland.

With war increasingly likely, propaganda became the main weapon with both sides seeking to steadily chip away at the morale of the other.

Loudspeakers and posters nagged away at the opposition, the Germans trying to drive a wedge between the French and English, demanding that they consider whether it was worth dying for the Polish cause, and that the war itself was pointless.

In the political area, changes were afoot though. Neville Chamberlin found his position untenable after receiving strong criticism for the failure of the British campaign in Norway. This coupled with the failure of his appeasement of Hitler, led to him ultimately resigning as Prime Minister when Germany launched their invasion of France and the Low Countries and – despite a strong case for Lord Halifax becoming Prime Minister – this led to Winston Churchill being asked to form a government.

With the outbreak of war and the fear of mass bombings causing enormous civilian casualties, the large-scale evacuation of children and vulnerable people occurred from densely populated areas – likely target of bombers – to quieter, more sparsely populated rural areas, often outside the range of enemy bombers.

Codenamed Operation Pied Piper, the British government facilitated the evacuation of 1.5 million people – sometimes transporting them abroad to other parts of the British Empire. (Later evacuations were to occur after the Fall of France and the threat of the United Kingdom being invaded - via Hitler’s planned Operation Sealion - became a distinct possibility.)

Additionally, the United Kingdom received Channel Islanders and other displaced people from Continental Europe during this period, many pre-empting the inevitable Nazi invasion of their country and escaping to the United Kingdom, it’s relative geographic isolation from the rest of the continent - due to the English Channel - being seen as a natural barrier to Nazi expansion.