Lawmakers earlier this month rejected Prime Minister Theresa May's EU withdrawal agreement, which included a nearly two-year transition period to help minimize economic disruption. That defeat set up a series of votes in parliament on Tuesday through which lawmakers and the government will try to find a way forward.

The British currency edged a quarter of a percent lower to $1.3162 in early trading. Against the euro, it drifted 0.1 percent lower at 86.57 pence.

Growing optimism on the outlook for the pound fuelled a rally last week, sending the currency up 2.5 percent against the dollar last week, its biggest weekly gain since mid-September.