What does the High Court battle mean for Article 50?

The High Court has heard the final arguments in a historic case challenging Theresa May's right to trigger Article 50 to start the move to leave the EU.

A number of campaigners have mounted legal challenges against the Prime Minister's strategy for Brexit in what has been described as one of the most important constitutional cases in generations.

The applicants are asking top judges in London to rule that she is in danger of undermining the sovereignty of Parliament.

The judges said they would be taking time to consider the submissions and said a decision would be made "as quickly as possible".

What was thought of at first as a marginal case is now looking rather in the balance for the Government, with potentially huge significance for Brexit.


Image: Gina Miller, co-founder of investment fund SCM Private, is leading the high-powered legal challenge

Mrs May herself chose to up the ante in her first Conservative conference speech on the vote to leave the EU, accusing those behind the case of trying to subvert, kill and delay Brexit.

"They are insulting the intelligence of the British people," she said before announcing that she was going to send the Attorney General himself to "act for the Government" and "resist them in the courts".

I attended the court for most of the closing statements.

There were colourful references to Henry VIII, to the 1689 Bill of Rights, to the 1610 Case of Proclamations, and to the rights of lobster fisherman in Newfoundland after a Treaty with France in 1892.

Obviously.

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The crux of the claimants' case, led by Lord Pannick QC for one of the campaigners, businesswoman Gina Miller, is that the inevitable consequence of triggering Article 50 is that statutory rights enjoyed by some UK and EU citizens will be taken away.

That, the QC argues, can only be done by Parliament, and not by the executive using the crown prerogative.

Those rights include the right to stand and vote in EU elections, the right to refer a legal case to the European Court of Justice, and the right to ask the European Commission to help on a competition matter.

Then there are further rights of freedom of movement and of selling services also granted because of EU law.

"Notification will inevitably cause some statutory rights enacted by Parliament to be destroyed... It will take the preservation of other statutory rights out of the hands of Parliament... Prerogative cannot be used in order to take away, destroy, abrogate, a constitutional right that is recognised by statute," argued Lord Pannick.

Image: The legal action could end up in the Supreme Court in London

The Government QCs, led by Attorney General Jeremy Wright, argued that the mandate to trigger Article 50 is clear from the referendum.

They say that Parliament did not take the opportunity to prevent a restriction on the use of royal prerogative for the triggering of Article 50.

By deduction, the executive has the power to trigger as it pleases.

The Government also argued that there is no inevitability in losing EU rights - that will be a matter for negotiation.

Mr Wright said that "in reality, it seeks to invalidate the decision already taken to withdraw from the EU, and require that decision to be made by Parliament".

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The concerning news for the Government is that the three High Court judges appeared far more sceptical about its case than many had expected.

The Lord Chief Justice said twice that their argument "baffled" him.

It is entirely plausible that the Government will lose this case, which might come as a shock to Westminster.

Ultimately, it depends on the three judges.

It seems likely either way that an appeal will go to the Supreme Court to be heard by a full panel of Britain's top judges.

At this point, the Government might have to decide to change the terms of its argument, to perhaps say that Article 50 is reversible, so no rights are lost.

If the Government wins, it would be free to trigger as the Prime Minister wishes in late March.

If it loses, then Parliament could choose to pick when Article 50 is triggered, to agree a negotiating mandate, or "the need for Parliament to report back at defined times", suggested Lord Pannick.

Image: Thousands protested against Brexit outside the House of Commons

It is not impossible that the Supreme Court could refer the case to the European Court of Justice. This is one of the very same powers Gina Miller argues is being destroyed by Article 50.

This would appear to be the constitutional equivalent of breaking the space-time continuum.

In any event, this case is proving far more significant than had been presumed.

Even at this early stage in the High Court, a finding against the Government could impact on the currently febrile political climate in the Commons.

The Scottish Government and the Northern Ireland Assembly are watching very carefully too.

So the lawyers are being resisted in the courts. That doesn't mean the Government is going to win.