that he returned to HMS Vernon, where he was promoted to lieutenant commander on 15 November 1917, before transferring to the destroyer HMS Saumarez in September 1918. Willis transferred to the destroyer HMS Wallace in November 1918 and saw action against the Bolsheviks in the Baltic in early 1919, for which service he was awarded the Distinguished Service Order on 8 March 1920, and then transferred to the battlecruiser HMS Renown later that year and took part in the visit by the Prince of Wales to Australia and New Zealand. He returned to HMS Vernon again in 1921 and, having been promoted to commander on 30 June 1922, attended the Royal Naval Staff College. He became torpedo officer in the cruiser HMS Coventry in the Atlantic Fleet in December 1923 and then returned to the destroyer HMS Wallace as commanding officer in October 1927. Promoted to captain on 30 June 1929, Willis joined the directing staff at the Royal Naval Staff College in February 1930. He went on to be Flag Captain to the Commander-in-Chief, China Station in the cruiser HMS Kent in January 1933 and Flag Captain to the Commander-in-Chief, Home Fleet in the battleship HMS Nelson in May 1934. After that he became captain of HMS Vernon in September 1935 and commanding officer of the battleship HMS Barham in the Mediterranean Fleet in April 1938. Promoted to commodore on 2 February 1939, he became Chief of Staff to the Commander-in-Chief, Mediterranean Fleet, from February 1939 under Sir Dudley Pound, and, from June 1939 under Sir Andrew Cunningham. The Second World War Willis served in the Second World War initially on Cunningham's staff in which capacity, after promotion to rear admiral on 5 January 1940, he was involved in planning operations against the Italian Navy. Appointed a Companion of the Order of the Bath on 11 July 1940, he became Commander-in-Chief, South Atlantic with acting rank of vice-admiral in 1941 in which capacity he led actions against German and Japanese raiding ships. He then became Flag Officer commanding 3rd Battle Squadron and Second in command of the Eastern Fleet under Sir James Somerville with his flag in the battleship HMS Resolution in February 1942. In February 1943 he became Flag Officer commanding Force H, the force which covered North African Operations, the Allied invasion of Sicily in July 1943 and then the Allied invasion of Italy in September 1943.