In a significant moment of pre-World War II diplomacy, British Prime Minister Neville Chamberlain publicly pledged military support for Poland against the ominous threat of Nazi Germany on March 31, 1939. At a press conference in London, Chamberlain articulated Britain's resolve to aid the Second Polish Republic should it fall victim to aggression. This assurance was not just a show of goodwill; it marked a critical shift in British foreign policy, demonstrating an increasing willingness to confront the Nazi regime’s expanding ambitions in Europe.

The backdrop to this pledge was the rapid militarization and territorial expansion of Nazi Germany under Adolf Hitler, which had already annexed Austria and was eyeing Czechoslovakia. The Munich Agreement of September 1938 had failed to appease Hitler and, instead, had only emboldened him. Poland, sensing the growing threat, sought security guarantees from Western powers, prompting negotiations that culminated in Chamberlain's promise. In his address, he emphasized the importance of collective security and the moral duty to protect smaller nations from tyranny.

Chamberlain’s commitment to Poland would ultimately lead to an inevitable clash with Germany, as the latter invaded Poland just months later, on September 1, 1939, prompting Britain and France to declare war. The pledge reflected a broader strategy among British leaders to forge alliances against fascism and protect the balance of power in Europe, setting the stage for the ensuing global conflict.