The classical gold standard was destroyed by the belligerent governments during the First World War. The gold exchange standard of the 1920s permitted more monetary inflation by centralizing gold reserves in Great Britain and the U.S. and allowing other countries to hold pounds and dollars as reserves against their own domestic currencies. Take a look at Murray Rothbard’s book, A History of Money and Banking in the U.S.
https://mises.org/library/history-money-and-banking-united-states-colonial-era-world-war-ii
