European capitals and EU officials waited anxiously for the Supreme Court ruling and when it came the shock was just as intensely felt as throughout the United Kingdom. 

But Europe has also grown accustomed to one political detonation after another reverberating from Westminster. 

"Everyone was watching it with interest," said one official.  "No-one had expected it - but then again people no longer know what to expect." 

The European Commission's official response was predictable when asked if Boris Johnson was now a trustworthy negotiator. 

"It is not for us to comment on the internal constitutional matters of the United Kingdom," said a spokesperson. 

"Our interlocutor is the United Kingdom government and that remains the case." 

Guy Verhofstadt, the former Belgian prime minister and head of the Brexit Steering Committee in the European Parliament, was quick to put the boot in. 

"I never want to hear Boris Johnson or any other Brexiteer say again that the European Union is undemocratic," he tweeted.

"At least one big relief in the Brexit saga: the rule of law in the UK is alive & kicking. Parliaments should never be silenced in a real democracy." 

Norbert Röttgen, a German Christian Democrat MP close to Chancellor Merkel, tweeted: "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." 

Officials caution that the Supreme Court ruling may have carved out a milestone in British constitutional history, but it provides little strategic clarity on how Parliament will resolve the Brexit mess and how exactly Johnson intends to respond. 

There’s also the matter of the Tory Party Conference and how that event will play into Johnson’s actions. 

"It’s a bit early to draw conclusions because it’s so procedurally murky," mused one diplomat.

It is safe to say that the ruling appears to make a no-deal crash out at the end of October less likely.

Given the resounding and unanimous nature of the decision, the view is that Boris Johnson would not now dare to defy the law, as laid down in the Benn Act, that he seeks an extension to Article 50 by 19 October if he has failed to secure a deal with the EU in the meantime. 

Any attempt to sidestep that obligation through political chicanery will go straight back to the courts, is the view in Brussels. 

"It means the courts are not going to shy away from political questions," said one EU source. 

"The judgment reinforced the notion that the PM has no prerogative outside the law. These were pointed remarks, a warning for later. Even though the Benn Act is not foolproof, it sounds like the courts won’t shy away from making sure the law is abided by." 

Supreme Court president Lady Hale delivering the court's judgment

Diplomats are, however, cautious. "The dust has to settle on this a bit," said one senior EU source. "It’s an 11-0 judgment. It’s absolutely corruscating in its logic, so presumably [Johnson] is going to take account of it.  But he is not committing himself to any course of action." 

From Dublin’s point of view anything which diminishes the potential of a no-deal outcome at the end of October will be welcome in that it eases any pressure on Ireland to compromise on its backstop position. 

That pressure did not seem imminent. Last Friday, officials from 27 member states were told bluntly by the European Commission that the UK’s informal offer to date fell well short of what would be needed to replace the backstop and would have the effect of restoring a hard border. 

Had the UK offered something more magnanimous questions may have been asked as to whether or not Ireland could take a less absolutist approach. 

Even then, the EU’s positioning appears to be just as dogmatic on the integrity of the internal market question, as well as on the Irish peace process. 

Looking beyond the next few weeks, a lot of turmoil has to be endured before a pathway can be plotted into some kind of clarity. 

Boris Johnson could yet resign, and/or there could be a motion of no confidence followed by a caretaker government. 

A new prime minister appointed by Parliament would then abide by the Benn Act and seek an extension to Article 50, with a general election in November. 

This is terra incognita in procedural terms, says one EU source. But questions will immediately start to crystalise around what kind of conditions might be attached to the extension. 

France is likely to insist, once again, that it is not granted to simply facilitate more procrastination and can kicking.

The EU would also be wary of granting the extension to allow the UK to further pull at the threads of the backstop.So we would be back at the same set of intractable political forces.

Should Boris Johnson win an election, which is by no means out of the ordinary, he could come back with a majority that does not rely on the DUP. That may well move all sides back into the space of the Northern Ireland-only backstop, with moves concentrated on securing some concessions for the Northern Ireland Assembly on oversight of the backstop. 

Equally, a hung parliament cannot be ruled out, with more agony then on the cards.

What is clear is that the perception in Europe is that Boris Johnson is a diminished figure in terms of authority and trust. 

The view is that he has played fast and loose with the British constitution, he overplayed his hand in the expulsion of 21 Tory rebels and he is now subject to a form of rebalancing which could restabilise the turbulence of recent weeks.