On Sunday morning, after receiving grim reports on France, Churchill hurried from Chequers to London and called a special cabinet meeting. The cabinet authorized France to ask Germany about armistice terms, but only on the condition that the French fleet sail at once to British ports. Churchill had accepted that France was effectively lost, so his immediate goal became preventing the powerful French navy from falling into Hitler’s hands and shifting control at sea.

That same day, attention also turned to the German radio-beam threat. At a meeting of the RAF’s Night Interception Committee, R. V. Jones’s theory about a German beam navigation system was still doubted by senior figures such as Hugh Dowding and Henry Tizard. Frederick Lindemann pressed Churchill to treat the investigation as urgent, and Churchill backed him, giving the inquiry priority and turning an obscure technical issue into an active government concern.

On Monday, June 17, France effectively collapsed. Churchill’s cabinet learned that Marshal Philippe Pétain had replaced Reynaud and ordered the French army to stop fighting. Churchill then sent Pétain and Weygand a message warning that surrendering the French fleet would permanently dishonor them, and he urged them to send it to British or American ports while there was still time.

The French collapse shocked the British public, though many had feared it was coming. Civilians worried about British troops still in France and about the fate of the French navy and air force, while officials in London also felt a hard new clarity: Britain no longer had to accommodate a failing ally, and Dowding was relieved that Churchill would no longer be tempted to weaken Fighter Command by sending more fighters to France. At the same time, the strategic danger worsened because the Luftwaffe could now move to Channel bases, making invasion appear much more immediate.

Later that day, Churchill learned that the troopship Lancastria had been bombed and sunk with catastrophic loss of life. Fearing another blow to morale on the same day as France’s fall, Churchill suppressed the news, a decision that later fueled public distrust when the story emerged. On Tuesday, Lord Beaverbrook reported a dramatic rise in aircraft and engine production, offering badly needed encouragement, but the gains came from his abrasive methods, constant battles with the Air Ministry, and an aggressive salvage system that recovered wrecked aircraft, guns, and parts for rapid repair and return to service.