James pursued a career in the Royal Navy, rising to hold a number of important positions. Following early service on the training ship HMS
Britannia, he was confirmed in the rank of
sub-lieutenant on 15 April 1901. He was posted to the destroyer
HMS Skate on 7 October 1902, and promoted to
lieutenant later the same year, when in November he was posted to the
battleship HMS Venerable, on her first commission, to the
Mediterranean Fleet. He achieved the rank of
commander in 1913. During the First World War he served as
executive officer aboard the battlecruiser
HMS Queen Mary, leaving the ship shortly before it sailed to its doom at the
Battle of Jutland. He was flag commander to Vice Admiral
Sir Doveton Sturdee, commanding the
4th Battle Squadron of the Grand Fleet in
HMS Benbow from 1916 to 1917. Later in the war he assisted
William Reginald Hall, the Director of Naval Intelligence, eventually becoming a deputy director. Hall and James worked together in "
Room 40" which decrypted a number of crucial enemy signals relating to the
Battle of Jutland, the plans of
Roger Casement, and the
Zimmermann Telegram. At one point James ran Room 40 on Hall's behalf. James related some of the events in his biography of Hall, published in 1955. In the inter-war years, James served on the
China Station as captain of
HMS Curlew and chief of staff to the stations commander-in-chief from 1921 to 1922. From 1923, he was deputy director at the
Royal Naval College, Greenwich, and Director in 1925. In 1926 he returned as
flag captain of
HMS Royal Sovereign. He went on to be Naval Assistant to the
First Sea Lord in 1927, Chief of Staff to the
Commander-in-Chief, Atlantic Fleet, in 1929 and Chief of Staff to the
Commander-in-Chief, Mediterranean Fleet, in 1930. In 1932 he took command of the
Battlecruiser Squadron, with his flag in . He was promoted
vice admiral on 30 September 1933, and from 1935 to 1938 he was
Deputy Chief of the Naval Staff and a
Lord Commissioner of the Admiralty. He was appointed a
Knight Commander of the Order of the Bath in 1936. From 1938 James was a full
admiral. During the Second World War, James served as
Commander-in-Chief, Portsmouth, from 1939. In 1940 he commanded
Operation Aerial, the evacuation of British troops from
Brittany and
Normandy, a parallel operation to the
Dunkirk evacuation. In 1942 he was appointed as Chief of Naval Information, in charge of coordinating naval publicity. James was elected in 1943 as
Conservative Member of Parliament for the constituency of
Portsmouth North, which he held until 1945. He retired from the Navy in 1944. ==Retirement==