The currency may be assigned to users gradually over a period of time but you can make changes to your currency preferences at any time in your Wallet within the Uber app.
MoneySavingExpert.com is also advising Uber users to keep an eye out for an email which details the changes, and says this should contain a button which will take you straight to the correct setting page in your Uber app.
From this Thursday (February 27) your Uber account will automatically set British pounds as your “preferred currency” if you’re booking a trip in Canada, the US or any country using the euro.
"By default, Uber may assign your home currency as your preferred currency.
You may be charged variable conversion fees with an exchange rate set by your payment method provider, and foreign transaction fees may apply.