Sterling has plunged to a 31-year low, unsettling stock markets in early Asian trading amid concerns about Brexit.
The pound tumbled sharply, slumping as much as 6% to its lowest in more than three decades, before rebounding, with the reasons for the "flash crash" unclear.
The British currency, which would buy around 1.26 dollars on Thursday, plunged past the 1.20 level early on Friday before recovering minutes later, and it went on to trade at around 1.24 dollars.
Some market watchers blamed comments made by French president Francois Hollande, who insisted the European Union must take a tough stance in negotiating Brexit, while others suggested a "fat finger" trading mistake.
On Thursday, the pound was down 0.8% against the greenback at 1.264 dollars, as investors remained spooked by the Prime Minister's announcement on Tuesday that she will trigger Article 50 by March next year.
This is expected to herald a "hard Brexit", pulling Britain out of the European single market so the Government can tighten its grip on immigration.