Boris Johnson received the mother of all shocks on Wednesday morning when Scotland’s highest court ruled that the Prime Minister’s unprecedented decision to prorogue parliament for five weeks is illegal.

There were gasps in court as Boris’s strategy was struck down.

The three judges on the appeal court, chaired by Lord Carloway, Scotland’s most senior judge, will set out their reasoning in full on Friday but their summary concluded: “The Court will accordingly make an Order declaring that the Prime Minister’s advice to HM the Queen and the prorogation which followed thereon was unlawful and is thus null and of no effect.”

The summary said: “The Lord President, Lord Carloway, decided that although advice to HM the Queen on the exercise of the royal prerogative of prorogating Parliament was not reviewable on the normal grounds of judicial review, it would nevertheless be unlawful if its purpose was to stymie parliamentary scrutiny of the executive, which was a central pillar of the good governance principle enshrined in the constitution.”

Two of the other judges reached the same conclusion.

Lord Brodie’s thinking is set out: “This was an egregious case of a clear failure to comply with generally accepted standards of behaviour of public authorities. It was to be inferred that the principal reasons for the prorogation were to prevent or impede Parliament holding the executive to account and legislating with regard to Brexit, and to allow the executive to pursue a policy of a no deal Brexit without further Parliamentary interference.”

Lord Drummond Young’s said: “The circumstances, particularly the length of the prorogation, showed that the purpose was to prevent such scrutiny. The documents provided showed no other explanation for this. The only inference that could be drawn was that the UK Government and the Prime Minister wished to restrict Parliament.”

Even The Daily Telegraph, which is normally unquestioning in its support for

its columnist, conceded “parliament may have to be recalled”.

That will depend on what happens in the Supreme Court in London next week but it now looks as though the Queen herself has been sucked into a constitutional crisis because some lawyers are suggesting she was wrong to accept her Prime Minister’s advice that Parliament should be prorogued.

Since she has to go along with what the Prime Minister of the day tells her to do, she is damned if she does — and damned if she doesn’t.

A sense of what is happening in the UK was outlined by David Allen Green, a contributor to the Financial Times who specialises in law.

“The Scottish Court has found unanimously that the Prime Minister misled the Queen,” he said. “In effect, the court has held that Boris Johnson led to the Queen so as to obtain prorogation.

“Wow.

“Just wow.

“Not seen a court decision like this in thirty years of constitutional geekery.”

One thing is for sure. The Queen, who has remained studiously neutral in the 67 years plus since she came to the throne on February 6, 1952 — she has dealt with 14 Prime Ministers from Winston Church to Boris Johnson — will not appreciate being dragged into what has now become a full blown constitutional crisis.

She could have said “No” when Boris asked her to suspend Parliament but that itself would have triggered a crisis. Now, Scotland’s highest court, which overturned a decision by Lord Doherty that Boris’s action was not illegal, appears to be implying Her Majesty showed poor judgment in not resisting her Prime Minister’s advice.

“It’s a bit like a captain putting the Opposition in on a green wicket perfect for swing after winning the toss and then being crucified by cricket writers after the side batting first gets to 653 for 4 declared.

Catherine Haddon, senior fellow at the Institute for Government, said: “This is very embarrassing for the Queen and for Buckingham palace. To have a judgment that the advice given to her by the prime minister was unlawful puts the Queen in a very awkward position.”

Haddon said that MPs would have to wait until the Supreme Court judgment on September 17 to see whether parliament would continue to be prorogued. “But if the Supreme Court upholds the Scottish decision, the Palace will very quickly be on to the Prime Minister saying, ‘What do you intend to do?’ ”

The government will appeal to the Supreme Court, a spokesman at 10, Downing Street said. “We are disappointed by today’s decision and will appeal to the UK supreme court. The UK government needs to bring forward a strong domestic legislative agenda. Proroguing parliament is the legal and necessary way of delivering this.”

For Labour, the shadow attorney general, Bengali baroness Shami Chakrabarti took a personal swipe at Boris: “This ruling shows that, despite what Boris Johnson has spent his privileged life thinking, he is not above the law. Labour will not allow his elitist shutdown of parliament to enable him to dodge scrutiny and force through a disastrous no-deal Brexit.”

Jolyon Maugham QC, the legal campaigner whose Good Law Project funded the legal action on behalf of 79 opposition petitioners, said he and Aidan O’Neill QC, the group’s lawyer, were of one mind: “Our understanding is that unless the supreme court grants an order in the meantime, parliament is unsuspended with immediate effect. I’m relieved that my understanding of the functioning of our democracy – that allows parliament to exercise its vital constitutional role – has been vindicated by Scotland’s highest court. This is an incredibly important point of principle.”

Shadow Brexit secretary Keir Starmer, who was speaking at the TUC congress in Brighton when he learnt of the news, said the ruling was “huge”.

“I need to get back to Parliament, to see if we can reopen the doors and hold Johnson to account,' he declared.

Things are not going Boris’s way. A depiction of Boris as a “criminal” has been projected on to the side of the Houses of Parliament by the campaign group, Led By Donkeys.