Queen Mary as Churchill's mobile command post

How was RMS Queen Mary used as a command post and transport during the Second World War?

The liner carried troops on a vast scale and provided room for Churchill and his staff to work during transatlantic journeys.

Queen Mary's speed and space suited both troop transport and government work during transatlantic crossings. Churchill traveled aboard three times, listed on the passenger manifest as Colonel Warden. His 1943 crossing is connected with staff work on the Normandy invasion and a D-Day declaration. Wartime totals are given as roughly 800,000 troops carried and 600,000 miles steamed. The same large civilian liner could therefore move military personnel and provide working accommodation for senior leaders.