Winston Churchill's appointment as Prime Minister of the United Kingdom marked a critical turning point during World War II. Following the resignation of Neville Chamberlain, Churchill, known for his spirited rhetoric and leadership skills, took charge amid a growing sense of urgency as Nazi Germany escalated its military campaign. That same day, Germany launched a swift invasion of France, the Netherlands, Belgium, and Luxembourg, employing blitzkrieg tactics that caught many unprepared and underscored the effectiveness of their military strategy. This was a stark warning to Britain about the rising threat in Europe.

In addition to the political changes occurring in the UK, another significant action took place on the same day: British forces occupied Iceland. This operation aimed to thwart any possible German takeover of the strategically located island, which could serve as a base for attacks on North America and British shipping routes. By asserting control over Iceland, the British sought to maintain their naval dominance in the North Atlantic, further highlighting the geopolitical stakes of the conflict.

The concurrent events illustrated the urgency of the situation facing the Allies, leading to a re-evaluation of military strategies and alliances. Churchill's leadership was soon characterized by his powerful speeches and unwavering resolve, rallying the British public and setting the tone for a long and arduous struggle against the Axis powers.