London -- British lawmakers have backed a plan for Prime Minister Theresa May to go back to Brussels to reopen negotiations with the European Union over the draft divorce deal her government spent two years hammering out. Some of Britain's newspapers have hailed the Parliamentary Brexit vote as a triumph for the U.K. leader.

But as CBS News correspondent Charlie D'Agata reports, there's one big problem: EU officials have already said they're not going to budge. The British withdrawal agreement is, they insist, not open to renegotiation.

German government spokesman Steffen Seibert didn't mince words on the topic Wednesday, saying "opening up the withdrawal agreement is not on the agenda."

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The biggest sticking point is what to do about the border between Ireland, which is part of the EU, and Northern Ireland, which is part of the U.K.

The relevant part of the draft deal is the so-called Irish "backstop," which is meant to ensure goods and services can continue to flow back and forth as they do now, even if the U.K. leaves the EU without securing an all-encompassing trade and customs deal.

One thing the majority of lawmakers in London and Brussels do have in common is a desire to avoid a "no-deal" Brexit, with the U.K. crashing out of the union on the scheduled departure date of March 29 without any agreement in place.

Opposition Labour party lawmaker Jack Dromey said warned that proceeding with a no-deal Brexit would be contemptuous of parliament and impoverish the country.

"We're 58 days away from a cliff," he said. "If we plunge into an abyss our country will be a poorer country in every sense of the word."