This work is a close examination of the conditions surrounding and precipitating the last gasp of British naval hegemony and events which led to its demise. Great Britain undertook a massive naval building program in the late-1930s in order to deter aggression and secure dominance at sea against her nascent enemies, Nazi Germany and Fascist Italy. But the failure of the policy of Appeasement to deter war or delay it into the early 1940s left the building program only partially complete, and the exigencies of war led to the cancellation of the critical but costly and time-consuming "Lion" class battleships, and the slow delivery of the "1940 battlecruiser" (HMS Vanguard) and two vital fleet carriers. Adding to these issues the fall of France spurred the USA to initiate her own, even larger, naval building program, and the entry of the powerful and capable Imperial Japanese Navy completely overwhelmed Britain's position as the world's premier naval power. This book will be of value to those interested in the history of the Second World War, and the British navy.