At Chequers, Churchill decided to address the French people directly by BBC radio because he feared the Vichy government might align France’s remaining forces more closely with Germany. He wanted to reassure people in France and its colonies that Britain supported them and to encourage resistance, even though he could offer little practical help yet. Churchill insisted on composing the French version himself, dictated for hours without notes, and ordered arrangements for a twenty-minute broadcast split between French and English.

On Monday, Churchill kept revising the speech and struggled more with the French text than he had expected. A first translator sent by the Ministry of Information was too intimidated to make progress and was sent back to London. The ministry then sent Michel Saint-Denis, a bilingual Frenchman from the BBC, and Churchill finally accepted expert help. Churchill jokingly called the address his "frog speech," but he treated it seriously enough to rehearse, working with Saint-Denis on pronunciation and delivery.

That night, during an air raid, Churchill walked from Downing Street to the Cabinet War Rooms wearing his siren suit as anti-aircraft fire and falling splinters filled the sky. In the cramped BBC studio, Saint-Denis had nowhere to sit, so Churchill told him to sit partly on his knee while introducing him. Churchill then spoke to the French, declaring that Britain was still fighting, that the promised invasion had not come, and that Hitler remained the true enemy of France.

In the speech, Churchill urged the French not to obstruct Britain’s war effort and called on people even in so-called unoccupied France to resist. He warned that Hitler sought the destruction of the French nation, told French listeners to "rearm your spirits," and promised that Britain and the empire would never stop until Hitler was defeated. At Chequers, Mary Churchill listened with pride and recorded in her diary her hope that his words would restore French hope and courage.

When the broadcast ended in the war rooms, the listeners sat in moved silence, and Saint-Denis remembered Churchill rising with tears in his eyes and saying, "We have made history tonight." A week later in Berlin, Goebbels complained that more Germans were listening to the BBC and demanded harsher penalties for offenders. British intelligence later concluded that the crackdown had the opposite effect, making the forbidden broadcasts even more tempting.