UK Prime Minister Theresa May on Friday told MPs that Britain might stay in the European Union if they did not approve her deal next week.

The prime minister used a speech in Grimsby to urge the MPs who voted down her Brexit deal in January to support it next week, when she plans to put it back to the House of Commons.

"We may not leave the EU for many months, we may leave without the protections that the deal provides," May said. "We may never leave at all."

The UK is struggling to persuade the EU to make changes to the Northern Irish backstop that many MPs in Westminster say they cannot support.

LONDON — Theresa May has said that Brexit "may never happen at all" if members of Parliament vote to reject her deal for a second time.

The UK prime minister, who plans to put the Withdrawal Agreement to another House of Commons vote on Tuesday, said Parliament could vote for a delayed exit from the European Union if her deal with the EU is rejected, an outcome that could ultimately lead to the UK remaining in the EU.

"Next week MPs in Westminster face a crucial choice: whether to back the Brexit deal or to reject it," May said Friday afternoon in Grimsby, the coastal English city in an area that largely favored Brexit in the 2016 referendum.

"Back it and the UK will leave the European Union. Reject it and no one knows what will happen."

She added: "We may not leave the EU for many months, we may leave without the protections that the deal provides. We may never leave at all."

The prime minister also repeated her warning that delaying Brexit would not remove the prospect of a no-deal Brexit, which would result in disruption for British people and businesses.

"Because if MPs reject the deal, nothing is certain," she said. "It would be at a moment of crisis."

"MPs would immediately be faced with another choice. Either we leave the EU with no deal on 29 March. I do not believe that would be the best outcome for the UK or the EU.

"Or we delay Brexit and carry on arguing about it, both amongst ourselves and with the EU. That's not in our interests either.

"More talking will not change the questions that need to be settled."

The prime minister's speech came after Geoffrey Cox, the UK attorney general, canceled a planned trip to Brussels in a sign that his attempt to persuade the EU to allow changes to the contentious Irish backstop had failed.

Multiple reports indicated that there was a sizable gulf between the demands of EU and UK officials.

The UK has demanded legally binding changes to the backstop, an insurance mechanism designed to avoid a hard border between Ireland, which would remain with the EU after Brexit, and Northern Ireland. The backstop is widely opposed by Conservative MPs who say it could keep the UK indefinitely trapped within the EU customs union.

The Democratic Unionist Party, which props up May's government, also opposes the latest backstop proposal, as it would create new border checks between Northern Ireland and Great Britain.

The EU, however, has repeatedly indicated that it will not make significant concessions to the backstop, leading to gridlocked talks this week and raising the likelihood that May's deal will suffer another heavy defeat. It was defeated by a crushing 230-vote margin in January.