The collapse of the Anglo-French alliance in 1940 was a bitter “divorce” fueled by strategic divergence and mutual suspicion. As the military situation deteriorated, Britain refused to commit its air reserves to the lost battle in France, prioritizing island defense. The evacuation of Dunkirk, viewed as a miracle in Britain, was seen in France as a betrayal where the British army escaped while the French rearguard was sacrificed. This animosity exploded with the British attack on the French fleet at Mers-el-Kébir, killing nearly 1,300 French sailors. This act solidified the legitimacy of the Vichy regime, allowing Pétain to portray Britain as a hostile power and justifying collaboration with Germany as a defensive necessity.