The pound came under pressure on Monday as currency traders reacted to Britain's loss of its AAA credit rating. On Friday, Moody's cut the rating to AA1.
The value of sterling has been edging down for several weeks following concerns about a worsening outlook for the economy.
During early trading on Monday, sterling dropped as low as $US1.5069 against the dollar, its lowest for 2½ years, before recovering to $US1.514.
Against the euro, the pound was worth 1.148 euros, its lowest for 16 months.
The BBC reports the pound has lost about 7% of its value against the dollar and euro this year.
