Britain’s pound tumbled Monday after a member of Prime Minister John Major’s Cabinet challenged him as leader of the Conservative Party, the latest sign of British political turmoil.

The dollar ended mostly higher.

Sudden shifts in political leadership can undermine a currency and send investors elsewhere until the tumult subsides.

“It’s certainly true that sterling has been hit,” said John Ryding, a senior economist with Bear, Stearns & Co.

Ordinarily, a drop in the pound can hurt the dollar because it sends investors into marks and other European denominations, indirectly reducing demand for the U.S. currency.

Exchange Currency in Dollars Dollar in foreign currency Canada .7287 1.3723 France .2053 4.8705 Germany .7193 1.3903 Great Britain 1.5830 .6317 Italy .000614 1628.50 Japan .011864 84.29 Mexico .160128 6.2450