Chatfield became First Sea Lord in January 1933 and was advanced to Knight Grand Cross of the Order of the Bath in the 1934 New Year Honours. As First Sea Lord he won arguments that the Royal Navy should have 70 cruisers rather than the 50 cruisers that had been agreed at the London Naval Conference 1930, that the battleship still had an important role to play despite the development of the bomber and that the Fleet Air Arm should be part of the Royal Navy rather than the Royal Air Force.