DUBLIN (Reuters) - Irish Prime Minister Leo Varadkar said on Thursday the European Union would not accept clarifications or reassurances on Britain’s Brexit deal that would undermine the spirit of the agreement or render any part of it inoperable.

FILE PHOTO: Ireland's Prime Minister (Taoiseach) and Defence Minister Leo Varadkar attends a news conference after a European Union leaders summit in Brussels, Belgium December 14, 2018. REUTERS/Piroschka Van De Wouw

British lawmakers are due to decide later this month whether to accept Prime Minister Theresa May’s plans for a managed exit and relatively close economic ties, or reject the deal and spawn uncertainty about the country’s next steps.

Before the vote, May is seeking last-minute reassurances from the European Union over the Irish backstop - an insurance policy to avoid a hard border between the British province and EU-member Ireland.

“We want to be in a position to give guarantees, give assurances, give clarifications (but) we need to know what the United Kingdom parliament wants,” Varadkar told journalists in Dublin.

“But they need to also understand that there will be no explanation, guarantee or clarification that contradicts or renders inoperable any part of the withdrawal agreement,” he said.

Varadkar said he had a long “brainstorming” conversation with German Chancellor Angela Merkel on Thursday in which the two leaders agreed that Britain not the EU would need to come up with a proposal to overcome the impasse.

Varadkar said he had “given up speculating” on whether Britain would leave the European Union without a deal.

But he said his government was now addressing preparations for such an outcome with the same seriousness as it was addressing preparations for an exit under May’s deal.

Varadkar’s advisor is due to speak to one of May’s advisors on Thursday he said.

Asked about a demand by some pro-Brexit British lawmakers that the backstop be temporary, Varadkar said it was temporary in that it “would apply on a temporary basis unless or until new arrangements supersede it.”

(This story corrects paragraph 8 to say Ireland now addressing preparations for a no-deal Brexit alongside those for one under May’s deal.)