Upon his return from Woking, Poett was transferred to the War Office, and by early 1941 he had been promoted to lieutenant-colonel and became the General Staff Officer Grade 1 in charge of the Staff Duties 2 branch of the War Office. Poett was given a secretary to help him handle his new responsibilities, many of which were secret in nature; they included developing the Orders of Battle for oversea theatres such as the Middle East, and the allocation of space on convoys travelling to these theatres. At one point Poett had to defend a paper he had written, about the Middle East Order of Battle, to the Prime Minister Winston Churchill, who was unhappy with the large number of administrative units assigned to the theatre. Poett continued his work throughout 1941, and in late December he travelled to Washington D.C. in the United States of America alongside an officer from the Plans Directorate, with orders to assist the Anglo-American planning of the coming conflict. These initial planning meetings ended in January 1942, and Poett returned with the Prime Minister's party via a specially-charted train to Norfolk, Virginia, and then by flying boat to Britain via Bermuda; when he was leaving the hotel he had been staying in, Poett was informed that his hotel bills and expenses had been paid for by the Americans as part of the Lend Lease agreement between the two countries.