London, December 10 (RHC)-- British Prime Minister Theresa May on Monday abruptly pulled a parliamentary vote on her Brexit deal, throwing Britain's plan to leave the European Union into chaos after admitting that she faced a rout. 

May's move on the eve of a crucial parliamentary vote opens up an array of options for the United Kingdom, including a disorderly Brexit with no deal, another referendum on EU membership, or a last minute renegotiation of May's deal. 

Announcing the delay, May was laughed at by some lawmakers when she said there was broad support for the deal and that she had listened carefully to different views it -- the result of 18 months of tortuous negotiations. 

"If we went ahead and held the vote tomorrow the deal would be rejected by a significant margin," May told parliament, adding that she was confident it was the right deal.  "We will therefore defer the vote scheduled for tomorrow and not proceed to divide the House at this time," May said, adding that the United Kingdom would step up planning for a no-deal Brexit. 

May accepted there was concern among lawmakers about the Northern Irish 'backstop', an insurance policy aimed at avoiding a return to border checks between the British province and Ireland that could threaten a 1998 peace accord. 

Her critics, both supporters of Brexit and its opponents, have rejected the open-ended backstop, which could require Britain to accept European Union rules indefinitely, long after it gives up any say in drafting them. 

She said the broader question was whether parliament wanted to deliver on the will of the people for Brexit, or open up the divisions in the world's fifth largest economy with another referendum.   Sterling skidded to its weakest level since June 2017, falling to $1.2622. 

May's own position is uncertain and she could face a swift challenge. Main opposition Labour Party leader Jeremy Corbyn said the United Kingdom no longer had "a functioning government."  A small Northern Irish party which props up May's Conservative minority government called the situation a shambles.  Scottish nationalists pledged to support a vote to bring the government down. 

The decision to halt the vote came just hours after the EU's top court ruled that Britain could unilaterally withdraw its decision to leave the bloc on March 29th.