[Cronos]

Before 1914, Britain was a patriotic, self-confident country, proudly imperialist, proudly expansionist, and economically very vibrant. The carnage of the war caused us to check. If the policies and assumptions of our culture were so good, how come they led us to a disastrous war that cost over a million lives?

well, yes it may have started the decline, but British culture was still strong until the 60s.

[Vanders9]

True, but British Culture was very very strong - the country had been unusually successful for a very long time - and that had created a very strong collection of social bonds. It takes time to unravel something like that. I’m not suggesting there have not been many other factors - you rightly point to the hedonistic self-indulgence of the drug and “free love” sixties - but it was the first world war that started the decline.