第一海軍卿
John became First Sea Lord and Chief of the Naval Staff in May 1960. He was advanced to Knight Grand Cross of the Order of the Bath in the 1960 Birthday Honours. As First Sea Lord he was primarily concerned with plans for the building of the CVA-01 aircraft-carriers (which were eventually cancelled in 1966). During his tenure as First Sea Lord, he provided an introduction to all episodes of the ATV series ‘War at Sea’. He was promoted to Admiral of the Fleet on 23 May 1962 and retired in August 1963.