If the cataclysm of the first world war had destroyed any belief in the immutability of a civilisation based on liberal, progressive British values, the origins of the morbid age can also be found in developments in the natural and social sciences that occurred well before 1914.
History suggests that, in the absence of nuclear deterrence, the world would eventually be plunged yet again into the sort of cataclysm that twice scarred the 20th Century.