 The Washington Naval Treaty in 1922 provided for a 5 : 5 : 3 ratio of capital ships of the British , United States and Japanese navies . Throughout the 1920s , the Royal Navy remained the world 's largest navy , with a comfortable margin of superiority over Japan , which was regarded as the most likely adversary . The Washington Naval Treaty also prohibited the fortification of islands in the Pacific , but Singapore was specifically excluded . The provisions of the London Naval Treaty of 1930 , however , restricted naval construction , resulting in a serious decline in the British shipbuilding industry . Germany 's willingness to limit the size of its navy led to the Anglo @-@ German Naval Agreement of 1935 . This was seen as signalling a sincere desire to avoid conflict with Britain . In 1934 , the First Sea Lord , Admiral Sir Ernle Chatfield , began to press for a new naval build @-@ up sufficient to fight both Japan and the strongest European power . He intended to accelerate construction to the maximum capacity of the shipyards , but the Treasury soon became alarmed at the potential cost of the program , which was costed at between £ 88 and £ 104 million . By 1938 , the Treasury was losing its fight to stop rearmament ; politicians and the public were more afraid of being caught unprepared for war with Germany and Japan than of a major financial crisis in the more distant future . 
