The pound was long the symbol of Britain's economic might. The chaos surrounding Brexit, the country's 2016 decision to leave the European Union, has sent the currency falling sharply.

A version of this article appears in print on Sept. 29, 2022, Section B, Page 1 of the New York edition with the headline: Pound’s Swoon Echoes Declines in British Power, Past and Present.

The pound’s value was double that of the U.S. dollar as recently as 2007. In late September 2022, one British pound fell to about $1.05. That marked the lowest price ...