Between 1870 and 1914, there was a 45-year span of rising living standards, stable prices, massive capital investment and prolific technological progress. In terms of overall progress, these four-plus decades have never been equaled — either before or since.
Then came the Great War. It involved a scale of total industrial mobilization and financial mayhem that was unlike any that had gone before. In the case of Great Britain, for example, its national debt increased 14-fold.
In addition, England's price level doubled, its capital stock was depleted, most offshore investments were liquidated and universal wartime conscription left it with a massive overhang of human and financial liabilities.