Berlin and other European capitals reacted with strained optimism on Thursday morning to news of cabinet backing for the Brexit deal. But that optimism began to fray as the day wore on amid a growing heave against the British prime minister.

With characteristic sobriety Chancellor Angela Merkel noted that both British and EU officials had backed the proposal, followed by Mrs May’s cabinet.

“As far as Brexit question goes I am very glad at success in what were long and not always easy talks, and that a proposal could be reached,” she said. “We have to examine how far the 27 member states can go along with this . . . we have to analyse all the many pages.”

Aware of the growing tensions in London, the German leader insisted that everyone must be aware of the alternative to the deal agreed this week: a disorderly Brexit.

“This is an alternative we must always stay mindful of,” she said. “The question is: is what we have now a foundation? I hope that it can be a foundation.”

Her finance minister Olaf Scholz insisted a no-deal Brexit would be “awful” for the British economy and “problematic” for the rest of the EU. That a draft agreement was struck, he said, “shows that, in European politics optimism is a good principle”.

Optimism in short supply

Optimism was in short supply in Berlin’s foreign ministry where minister Heiko Maas pointed out that Brexit remained a decision Germany “regretted” and must not be allowed undermine the single market.

His deputy, Europe minister Michael Roth, was even more pessimistic, saying: “I worry that nothing will come of this because no majority will be found in the British parliament.”

Elsewhere in Europe, ministers did their best to make the best of an uncertain situation.

French finance minister Bruno Le Maire said the proposed withdrawal agreement was “good news for the French economy and good news for all French firms”. “It’s in everyone’s interest that Brexit should go ahead smoothly”, he told French television, warning that EU rules must be respected if Britain remains in the customs union. The deal “must not weaken our common market”, he added.

Sweden’s EU minister Ann Linde says Sweden will vote ‘yes’ to the draft Brexit withdrawal deal, saying it contained nothing problematic from a Swedish perspective and protects the rights of Swedes living and working in the UK.

Across Europe, Brexit was a big, but by no means, only story in the news on Thursday. And it barely featured in the first of a series of debates between three would-be successors to Angela Merkel as leader of the Christian Democratic Union (CDU) next month.

Mr Friedrich Merz, a conservative liberal hopeful, was the only candidate to even mention Brexit in his opening remarks in the northern German city of Lübeck. He warned CDU delegates the country had to be prepared for all eventualities: “We could get news this evening not of an orderly but a disorderly Brexit.”