Anglo–Polish Pact of Mutual Assistance

European history

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July 21, 2026

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The Anglo-Polish Pact of Mutual Assistance was a treaty signed on August 25, 1939, between the United Kingdom and Poland. This pact solidified a commitment of mutual military support in the event of aggression.

Following Germany's demands for the return of Danzig and passage across Polish territory, Poland, with British backing, refused. This led to Hitler denouncing the German-Polish Nonaggression Pact and signing the Pact of Steel with Italy. Crucially, Hitler also secured the Nazi-Soviet pact, which secretly divided Eastern Europe and Poland between Germany and the Soviet Union.

Despite the Nazi-Soviet pact, Britain and France reaffirmed their commitment to Poland. When Germany invaded Poland on September 1, 1939, Britain and France declared war on Germany, marking the beginning of World War II.12

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Third Reich
Poland’s refusal
…with the signature of a pact of mutual assistance between Great Britain and Poland (August 25), Hitler attempted to avert British intervention through further negotiations. The British, however, refused to bring pressure to bear on the Poles, and on September 1 the German army invaded Poland. Two days later Great…
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…with the signature of a pact of mutual assistance between Great Britain and Poland (August 25), Hitler attempted to avert British intervention through further negotiations. The British, however, refused to bring pressure to bear on the Poles, and on September 1 the German army invaded Poland. Two days later Great…
Read More