Campaigners outside the Houses of Parliament.
Sterling has rallied this week - it is up 1.7 percent against the dollar - after British lawmakers voted against leaving the European Union without a deal and backed a delay to the March 29 exit date.
After months of political deadlock, Britain's House of Commons voted 413-202 Thursday to ask the E.U.to delay the country's exit.
Weston-super-Mare MP John Penrose voted in favour of the extension while the Wells and North Somerset representatives both opted against it.
The UK Parliament will hold a number of important votes on the future of the Brexit process in the next few days, which will determine the nature of the future UK-EU relationship.
The European Commission said it would be down to the bloc "to consider such a request, giving priority to the need to ensure the functioning of the EU institutions and taking into account the reasons for and duration of a possible extension".
Article 50 was triggered on March 29, 2017 with the United Kingdom scheduled to leave at 11pm United Kingdom time later March 29, 2019.
A senior government source said that persuading the DUP would be key to securing parliament's approval, as that would prompt eurosceptic Conservatives to back the deal.
Theresa May could simply put her deal to a vote again.
The Brexit deadline is legally binding and can not be extended without the agreement of all other 27 European Union countries.
The short delay envisaged in the motion could last until June 30, but the longer extension is not now time-limited.
Theresa May leaves 10 Downing Street. Mrs May's spokesman has said that the government was still making preparations in the event of a no-deal divorce.
Even if the deadline is unanimously agreed, the Prime Minister will still need to get a deal through the Houses of Commons, which is now divided on the matter of the Irish back-stop.
May hopes that this can convince enough MPs to start supporting her deal.
Because of the deep divisions in Tory ranks on the issue of extending Article 50, Mrs May granted a free vote to her MPs.
But despite the Prime Minister's Commons victory, she suffered a further blow to her leadership as eight Cabinet ministers - including the Brexit Secretary Stephen Barclay - voted against the plan, with Chief Whip Julian Smith abstaining. The official People's Vote campaign echoed Labour's reticence, saying in a statement: "We recognise there is a range of opinions on when to press the case for the public being given the final say, which means some of these MPs will vote for the Wollaston amendment, some may vote against, and some will abstain".