Brussels officials think Boris Johnson has lost control and will not be able to crash UK out

The UK supreme court ruling against Boris Johnson was celebrated in EU capitals and has left Brussels convinced that the prime minister has lost control of events and will not be able to crash Britain out on 31 October.

As Lady Hale, the president of the UK’s highest court, read out its unanimous judgment, politicians, officials and diplomats involved in the Brexit talks spoke of their reassurance about the state of the rule of law in the UK.

The decision to prorogue parliament for five weeks in order to avoid parliamentary scrutiny had already provoked criticism by senior politicians in the European parliament, and the court’s confirmation on Tuesday that Johnson’s move was unlawful was welcomed.

Guy Verhofstadt, the EU parliament’s Brexit coordinator, tweeted: “At least one big relief in the Brexit saga: the rule of law in the UK is alive & kicking.

Boris Johnson's suspension of parliament unlawful, supreme court rules Read more

“Parliaments should never be silenced in a real democracy. I never want to hear Boris Johnson or any other Brexiteer say again that the European Union is undemocratic.”

The European parliament’s speaker, David Sassoli, said: “Important decision from UK supreme court to rule prorogation of parliament as unlawful.

“Any Brexit agreement needs to be approved by both UK and EU parliament, so proper democratic scrutiny on both sides of the Channel is essential.”

The chair of the Bundestag’s foreign affairs committee, Norbert Röttgen, who is a senior member of Angela Merkel’s CDU party, expressed his satisfaction at the judgment.

Play Video Reaction as supreme court rules Boris Johnson's proroguing of parliament was unlawful – watch live

He said: “It is not my place to comment on judicial proceedings in Britain. But as a fellow MP I do feel the need to express my joy and solidarity with British parliamentarians.”

A former head of the EU council’s legal service, Jean-Claude Piris, tweeted: “It gives me good and emotional feelings too.

“It was so sad to see this great country at the risk of being led to no longer respect the principles and values upon which its democratic institutions have been built over centuries.”

But sources said it was also clear now that Johnson had little hope of presenting MPs with the choice of leaving, “do or die”, with or without a deal on 31 October.

The prime minister is seemingly constrained by the Benn Act, which would instruct him to seek an extension if a deal is not agreed with the EU and backed by the Commons, but Johnson had suggested he would find a way around the law.

The ruling has confirmed to Brussels that parliament is in the driving seat and able to instruct the prime minister as it wishes over the coming weeks, with an increased chance of a general election next month, and a reduced possibility of a deal being agreed and passed by the Commons next month.

Play Video 1:34 Boris Johnson: supreme court ruling has made getting Brexit deal harder – video

One EU diplomat said: “Another domestic in this long Brexit saga. Parliament hasn’t been able to formulate a position in the last three years so why would they suddenly now?

“Without decisive action their government is driving this process off the cliff. But seeing as Brexit was about the sovereignty of parliament it was bewildering that government moved to suspend it. So much about this process is contradictory and utterly mind-blowing.”

EU officials think the court ruling has increased the chances of an extension request from the UK. “Are the chances of an extension request probably very high? Yes,” said one source. “And has the court’s judgment made the chances higher? Cautiously yes. And is the EU banging its head against a brick wall saying: ‘When is this going to stop?’ Absolutely.”

Fabian Zuleeg, the chief executive of the European Policy Centre thinktank, tweeted: “Conclusions? 31 October no deal unlikely unless Boris Johnson is willing to break law and won’t be stopped.

“So Boris Johnson only has two real options: resign and fight election on clear no-deal stance or make deal, capitulating in negotiations. Former looks more likely but unlikely to bring resolution.”

The Irish taoiseach, Leo Varadkar, said the issue was an “internal matter” for the UK. “Whoever is prime minister of the United Kingdom is somebody we’re going to work with,” he said. “It’s not for us to decide who the prime minister of the UK is.”

Asked whether the ruling would impact on the EU’s trust in Johnson, a European commission spokeswoman said: “We have all seen the news but it is not for us to comment on the internal constitutional matters of the United Kingdom. Our interlocutor is the United Kingdom government and that remains the case. All other judgments I leave to you.”