During the Second World War, the company benefited from the huge demand for steel by the military; however, financial calls from his associates, who needed or wanted to liquidate positions as a result of the French collapse, bedeviled Dunn, who retained in the end his Algoma shares and nothing else. Even then, he mortgaged them to his stockbroker friends. The benefit from a subsidized price for sinter, granted at the corporate nadir of 1935 by the provincial government of Mitchell Hepburn, was cancelled in 1942 by the Conant government. At times Dunn's relationship with the federal government minister in charge of the war effort, C. D. Howe was difficult; Beaverbrook relates a story in which he had to calm Winston Churchill because Howe or Mackenzie King, in the dark days of October 1940, had shredded Dunn's reputation. Howe threatened Dunn on 26 October 1940 with effective expropriation under the War Measures Act and the National Resources Mobilization Act: the government might obtain control of "trading, exportation, importation, production and manufacture" works, and require him "to place [his services and property at the disposal of His Majesty in right of Canada, as may be deemed necessary or expedient for securing the public safety, the defence of Canada, the maintenance of public order, or the efficient prosecution of the war, or for maintaining supplies or services essential to the life of the community." A letter to Churchill from Beaverbrook, who at the time was in the former's Ministry, was enough to secure the person and property of Dunn, but his health suffered ill effects, as presently will be related. The week after Dunn had a major surgery, Howe struck again. This time, Howe telephoned on 12 April 1943 to Wilson at the Royal Bank: if Howe's steel experts (likely the same experts Dunn had wrongfooted in the siderite development) were right, either Dunn must stand down from his Chairmanship of Algoma, or he would be forced to expropriate. Many precedents had accumulated over three years, both in the UK and Canada. But Wilson and his Royal Bank stood firm and refused to countenance this extreme. Wilson instead asked for disclosure of the government file, and Howe's bluff was shot. By August 1943, a vice-president at Algoma was removed and the way forward was clear.