The Second World War was the most destructive conflict in human history. Years of international tension and aggressive expansion by Fascist Italy and Nazi Germany culminated in the German invasion of Poland on 1 September 1939. Britain and France declared war on Germany two days later.

The decisions that led to war reflected the ambitions, rivalries, fears and anxieties that developed in the two decades that followed the end of the First World War. The European powers were willing to go to war to extend or protect what each nation saw - in dramatically different ways - as matters of vital interest, great power status, international prestige, and national survival.

The Legacy of the First World War

The First World War and its subsequent peace settlements gave rise to new ambitions, rivalries and tensions. People had high expectations that the post-war peace settlement would create a new world order and ensure that the slaughter of the First World War was never repeated.

The Treaty of Versailles, signed in June 1919, created the League of Nations - an international body intended to promote peace and prevent war. However, the treaty was an uneasy compromise as each of the victorious Allies - Britain, America, France and Italy - looked to pursue their own interests. Germany was forced to surrender territory, disarm and pay for the war's damage. These divisive conditions were criticised as overly vindictive by many in Britain and America. The treaty's terms caused immediate outrage and lasting bitterness in Germany.

The sense of defeat, humiliation and injustice would have a significant impact on German foreign and domestic policies, and calls to revise the terms of the treaty became a major aspect of international politics in the 1920s and 1930s. The period between the two world wars was one of instability and insecurity. Political, economic and social unrest was made worse by the collapse of the international economy in 1929.

(© IWM Art.IWM ART 2856) The signing of the Treaty of Versailles, depicted in a painting by William Orpen.

The Retreat from Democracy in Europe

The instability and insecurity of the 1920s and 1930s gave rise to political extremism in many European countries. People looked to authoritarian leadership as a political alternative. Fascist leader Benito Mussolini came to power in Italy in 1922 and almost all aspects of Italian life came under state control. 

(© IWM MH 11040) Adolf Hitler, flanked by the massed ranks of the Sturm Abteilung (SA), ascends the steps to the speaker's podium during the 1934 harvest festival celebration at Bückeburg.

In Germany, Adolf Hitler became Chancellor in 1933 and established a totalitarian one-party state under the Nazis. Political opposition was violently repressed. Hitler exploited the popular belief that Germany had been humiliated after the First World War. He promised economic recovery, national revival and that Germany would return to international prominence through a revision of the Treaty of Versailles.

Germany withdrew from the League of Nations in October 1933. In 1935, Hitler announced German rearmament and re-introduced conscription, which was prohibited under Versailles. The ultra-nationalist governments of both Italy and Germany each pursued aggressive foreign policies of territorial expansion that threatened to destroy the world order established by the post-war peace settlement.

Italy and Germany on the March

On 3 October 1935, Italy invaded Abyssinia (present day Ethiopia). Both countries were members of the League of Nations, and Italy's aggression compelled the League to intervene. However, Britain and France struggled to coordinate an effective response. They imposed limited economic sanctions, which only pushed Italy away from Britain and France and into closer co-operation with Germany. Encouraged by the weak response to Italy's attack on Abyssinia, Hitler sent troops into the Rhineland on 7 March 1936. This demilitarised zone had been established under the Treaty of Versailles as a buffer between Germany and France. Britain did not see the occupation as a threat to its interests or overall security and did not respond militarily. France, already politically and militarily insecure, was left feeling isolated internationally and did little to resist the occupation. Hitler's success in the Rhineland encouraged him to pursue an even more aggressive foreign policy. Intervention in the Spanish Civil War, which broke out in July 1936, reinforced the divide between Italy and Germany on one side, and Britain and France on the other.

(© IWM MH 13118) German troops march into the Rhineland on 1 March 1936.

Germany Expands

Hitler's ambitions for German expansion became increasingly evident throughout 1938. German troops marched into Austria on 12 March and, with the enthusiastic support of most Austrians, the country was annexed to Germany the next day. There was little international resistance to this Anschluss, which many viewed as a natural union. However, Hitler's demands for the German-speaking areas of Czechoslovakia created a crisis that brought Europe to the brink of war in September 1938.

The multi-ethnic state of Czechoslovakia had been created towards the end of the First World War. Many Germans living in Czechoslovakia wanted to re-join Germany. Most lived in an area along the German and Austrian borders, known as the Sudetenland. In the summer of 1938, Hitler threatened war if the Sudetenland was not ceded to Germany. Britain and France, although in the process of rearming, did not yet feel able to confront Hitler with force. But by 27 September, both had reluctantly accepted that they would go to war if German troops entered Czech territory without international agreement. The next day, Hitler agreed to an international conference to resolve the Sudeten issue.

(© IWM MH 13129) Adolf Hitler enters Vienna.

Britain Appeases

The Italian, British, French and German leaders met in Munich on 29 and 30 September. They agreed to accept German annexation of the Sudetenland and the British secured a peace pledge from Hitler. Czechoslovakia was not invited to take part in the discussions, but was forced to accept the Munich Agreement. Appeasement is the name given to Britain's policy of accepting German expansion in Europe in the 1930s. It developed in response to Britain's assessment of its political, economic and strategic situation and was heavily influenced by strong anti-war sentiment. 

(© IWM D 2239) Neville Chamberlain, the Prime Minister, makes a brief speech announcing "Peace in our Time" on his arrival at Heston Airport after his meeting with Hitler at Munich, 30 September 1938.

Britain's renewed rearmament programme was not yet complete. Support from the Dominions was uncertain and France, Britain's ally in Europe, was weakened by political and economic crisis. Most Britons were desperate to avoid the destruction of another world war, a view shared by British Prime Minister Neville Chamberlain. Chamberlain sought to find a peaceful solution, but appeasement had its limits. Once Britain began to see German demands as a direct threat to its security or the security of its Empire, the tone of British policy began to change.

A Crisis Grows

The Munich Agreement removed the immediate threat of war and gave Britain time to continue preparing for a potential war. Yet Hitler's confidence only grew after Munich. He was certain that Britain and France would not use force to resist further German expansion. In March 1939, German forces occupied what remained of Czech territory. This convinced Britain and France that there were no limits to Hitler's territorial ambitions. They were now determined to prevent German domination of Europe - by force if necessary. 

(© IWM MH 13154) German Panzer II tanks in Wenceslas Square in Prague, 20 April 1939.

Recognising that Poland was likely to be Germany's next target, they gave guarantees to defend Polish independence. Britain and France, who had renewed their entente in February, began joint military planning. Both countries continued rearming and in April 1939 Britain introduced peacetime conscription for the first time in its history. However, war was still viewed as a last resort.

The Danzig Crisis

As Germany was completing its conquest of Czechoslovakia, another crisis was developing over the city of Danzig (present day Gdansk). Poland was one of several new countries born out of the First World War. The new Polish state was given access to the sea through a 'corridor' carved out of German territory. The former German city of Danzig was established as a Free City run by the League of Nations to serve as a major port for Polish trade. The creation of an independent Poland and the loss of Danzig created lasting resentment in Germany. 

(© IWM HU 39732) The Polish Foreign Minister, Colonel Józef Beck, is received by Adolf Hitler on his arrival at Obersalzberg.

In October 1938, the German Foreign Minister Joachim von Ribbentrop met with the Polish ambassador Josef Lipski to discuss Danzig's return to Germany. Discussions became more forceful at a meeting between Hitler and Polish Foreign Minister Józef Beck on 5 January 1939 (pictured here). However, the Poles refused to back down - Danzig was an issue over which they would fight. Polish resistance to German demands strengthened after Britain and France issued their guarantees to defend Poland's independence in March 1939. In April, Hitler ordered preparations for the invasion of Poland. He strengthened ties with Japan, the main threat to Britain's Empire in the Far East, and in May he signed a military alliance with Italy.

The Nazi-Soviet Pact

The Soviet Union had largely withdrawn from international affairs in the 1920s and early 1930s, but German hostility and the growing threat of Japan drove it to rethink its foreign policy and renew its relationship with Britain and France. But this relationship was marked by scepticism and distrust on both sides. Britain and France began talks with the Soviet Union in the summer of 1939, but the three powers struggled to reach an agreement and negotiations collapsed. 

(© IWM HU 39964) The Russo-German Non-Aggression Pact is signed by Vyacheslav Molotov, the Soviet Foreign Minister, under the watchful eye of Joseph Stalin.

Simultaneously, the Soviet Union was discussing a settlement with Germany. The Nazi-Soviet Non-Aggression Pact was signed on 23 August 1939, along with a secret protocol that left Hitler free to attack Poland without risking war with the Soviet Union and divided eastern Europe into German and Soviet spheres of influence.

Germany Invades Poland

In response to the Nazi-Soviet Pact, Britain and Poland entered into a formal military alliance on 25 August. The British still hoped for a peaceful solution, but continued preparing for war. The next few days were marked by frantic attempts to reach a settlement. Mussolini told Hitler that despite their military alliance, Italy would not fight. 

(© IWM HU 56131) German troops breaking the border barrier in the Polish town of Sopot (Zoppot) on the morning of 1 September 1939. The Soviet invasion would follow on 17 September.

Hitler offered to guarantee the safety of Britain's empire, but emphasised the need to 'solve' the crisis over Poland. On 29 August, Hitler presented British ambassador Sir Nevile Henderson with a set of minimum conditions for settlement, which included conceding both Danzig and the corridor. Hitler also made cursory demands for Poland to send a representative for direct negotiations within 24 hours. Britain and Poland refused. The situation became deadlocked. The German invasion of Poland began at 4.45am on 1 September.

Britain and France Declare War on Germany

Neville Chamberlain broadcast this announcement to the nation at 11.15am on 3 September. A British ultimatum demanding that Germany withdraw its troops from Poland had been delivered earlier that morning and expired at 11.00 without a reply. Britain was once again at war with Germany. The outbreak of war did not come as a surprise.

Tensions in Europe had been building for years and there was a growing feeling that German aggression needed to be confronted with force. The British reluctantly accepted that war was necessary to stop Hitler. Germany represented a direct threat to British security and the security of its empire. Accepting German domination of Europe had grave implications for British status and survival. Britain went to war in 1939 to defend the balance of power in Europe and safeguard Britain's position in the world.

(© IWM HU 5538) The Prime Minister, Neville Chamberlain, raising his hat to the crowd as he left 10 Downing Street on the day that Britain declared war on Germany, 3 September 1939.

'This country is at war with Germany'

BBC radio broadcast by British Prime Minister announcing declaration of war on Germany, 3/9/1939.

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HM King George VI and HM Queen Elizabeth talk to a woman operating a fuse testing machine during a visit to the Royal Ordnance factory in Blackburn.
© IWM (P 399)
Second World War

What The Royal Family Did During The Second World War

At 6pm on 3 September 1939, King George VI spoke to the people of Britain and the Empire. In his radio broadcast, he talked of the difficult times ahead and urged his people to stand firm.  
Churchill waving to crowds in Whitehall, London, as they celebrate VE Day, 8 May 1945.
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Second World War

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Winston Churchill became Britain's prime minister on 10 May 1940. As he was later to write: 'I felt...that all my past life had been but a preparation for this hour and for this trial'. On the very day that Churchill fulfilled his life's ambition, Germany had, that morning, invaded France, Belgium, the Netherlands and Luxembourg.
A Royal Air Force Lockheed Hudson Mk VI (AE626) aircraft of the Middle East Communications Flight flying over the pyramids.
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Visitors exploring the Second World War exhibition
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