On Saturday, February 8, Harry Hopkins prepared to leave Britain just as the Lend-Lease Bill cleared an important first hurdle in the U.S. House of Representatives. Before departing, Hopkins went to Chequers to say goodbye to Winston and Clementine Churchill and found Churchill drafting a radio speech for the next evening. Because the bill still faced the Senate, Hopkins urged Churchill to stress that aiding Britain would help keep America out of war rather than drag it in, and Churchill agreed. Churchill also planned to quote a handwritten note from Franklin Roosevelt containing lines from Longfellow.

Hopkins left a warm farewell note, then traveled toward Poole for a flight to Lisbon, but bad weather delayed his departure. Brendan Bracken came to see him off, and a British security agent was assigned to stay with Hopkins because of his carelessness with confidential papers, especially in espionage-ridden Lisbon. On Sunday evening, Hopkins, Bracken, and others gathered in the bar of the Branksome Tower Hotel to hear Churchill's broadcast.

In the speech, Churchill praised London's endurance under bombing, singled out the police, cited British successes against Italy in the Middle East, and pointed to Hopkins's visit as evidence of American goodwill. Following Hopkins's advice, Churchill argued that the United States did not need to send armies; Britain chiefly needed supplies and ships. He then warned that with spring would come a renewed and more dangerous invasion threat, including possible gas, parachute, and glider attacks, because Hitler had now had time to prepare properly. Churchill ended by invoking Roosevelt's poem and delivering his appeal: "Give us the tools, and we will finish the job."

The speech reached most of Britain and had a powerful effect. Some listeners found parts of it chilling, Goebbels dismissed it as insolent, and King George VI concluded that he could not have a better prime minister. Yet the immediate political result Churchill wanted did not come: the Senate still had not passed Lend-Lease, and British frustration grew as the debate dragged on.

In the following days, Churchill became increasingly convinced that the Luftwaffe was trying to kill him and strike the government by concentrating bombing on Whitehall. He pressed for stronger protection of the war rooms, questioned how many bombs had fallen near them, and continued to treat invasion as a serious danger even though intelligence suggested Hitler had postponed it. Churchill urged Hastings Ismay to prepare Home Forces and civilians, including clearing beaches and beach towns and warning residents that escape might become impossible once invasion began. At the same time, Beaverbrook pushed factories to work Sundays and round-the-clock shifts on aircraft frames and gas-decontamination equipment. As warmer weather briefly lifted spirits in London, Randolph Churchill sailed with No. 8 Commando for Egypt; he and Pamela hoped the separation might help repair their finances as she suspected another pregnancy, but Randolph's gambling habit still threatened that hope.