An extension is seen as necessary to avoid a no-deal scenario in which the UK would exit the bloc without agreements on key areas including trade, migration and security.
On Tuesday, members of parliament voted overwhelmingly to approve the extension request, with 420 votes in favour to 110 against.
In the last week, the rival parties have been meeting to agree upon a mutually acceptable Brexit plan and are set to meet again on Thursday. The controversial cross-party negotiations have aggravated divisions within both parties.
Twelve ministers from May’s own cabinet did not vote with the government, though it is unclear how many were deliberate abstentions and how many were approved absences.
Parliamentary approval secured, May will now have to request the extension at a key EU summit in Brussels on Wednesday.
‘There are no easy solutions’
The EU, which has already granted the UK one extension, has remained open to granting another only if May can guarantee parliamentary approval for a Brexit deal and give a clear indication how the extra time would be put to use.
However, a letter from European Council President Donald Tusk to council members may suggest a thaw in Europe’s stance.
In the letter, which was released shortly after the UK Parliament’s vote, Tusk said there was “little reason to believe” that May could persuade parliament to back a Brexit deal before the end of June, based on the fact that parliament has so far rejected May’s Brexit plan three times.
Tusk proposed granting an “alternative, longer extension” or a so-called “flexible extension” that would last no longer than one year and could be terminated automatically once the UK and EU agree upon a Withdrawal Agreement.
This, he said, would avoid a rolling series of short extensions, which “would almost certainly overshadow the business of the EU27 in the months ahead.
“The continued uncertainty would also be bad for our businesses and citizens,” Tusk said adding that “with Brexit, there are no easy solutions”.
May has been eager to avoid any extension that would require the UK to participate in the European Parliament elections, which begin on May 23.
May meets Macron, Merkel
May travelled to Paris on Tuesday in an attempt to secure the support of French President Emmanuel Macron, who has been firm on May’s need to deliver a clear plan for delivering Brexit.
Al Jazeera’s Natacha Butler, reporting from outside the Elysee presidential palace, said Macron may be adopting a more pragmatic approach.
“What we are hearing from Elysee sources is that Emmanuel Macron would be open to an extension but an extension that would be short, that would not roll into next year.
“It’s clear that the French president simply does not want this whole process to go any longer than it needs to,” Butler said.
Following the meeting, a Downing Street spokesperson said the leaders had discussed the ongoing talks with the Labour party, the European Parliament elections and the situation in Libya, where renegade General Khalifa Haftar‘s forces are fighting for control of the capital, Tripoli.
Earlier on Tuesday, May met German Chancellor Angela Merkel in Berlin, where the two discussed the “importance of ensuring Britain’s orderly withdrawal from the European Union, along with Libya and the war in Yemen, according to the spokesperson.
Merkel has previously vowed to fight “till the last hour” to avoid a no-deal Brexit.