Despite being the biggest courtroom in the Royal Courts of Justice, Court 4 was packed to capacity and beyond yesterday. Impressively, following a suggestion from our legal team,the court staff had arranged for live video links to screens elsewhere in the building. There was also live tweeting from Jolyon Maugham QC and Independent journalist, Siobhan Fenton and there has been some incisive discussion of the parties’ arguments in the NewLaw Journal and FinancialTimes. At the end of the day, a full transcript was published. Besides the many barristers instructed by those already involved in the case, there were QCs with ‘watching briefs’ present for the Scottish and Welsh Governments, suggesting they may want to step in on devolution issues when the case reaches the Supreme Court. So far, only the People’s Challenge has raised these issues in Court.

What follows are some highlights of the first court day and a taster of what’s to come.

Lord Pannick QC opened for the lead claimant, Gina Miller, telling the court that the litigation:

“raises an issue of fundamental constitutional importance concerning the limits of the power of the executive. Can the defendant, on behalf of the government, lawfully use prerogative powers to give a notification under Article 50 of the treaty on European Union of this country’s intention to withdraw from the EU?”

He added that he was going to adopt many “valuable points” made in the skeleton arguments from other parties supporting this side of the argument.

Lord Pannick then discussed the nature of Article 50, describing it as a “bullet” that, once fired, would reach its target sooner or later.

Next he covered the Referendum Act 2015 and the fact that the outcome does not bind Parliament:

“What is absent from the 2015 Act is any provision specifying what consequences, if any, should follow from the referendum result. The Act says nothing on that subject. And it is of interest that the Act says nothing on that subject, because when Parliament does wish to specify the consequences that should follow from a referendum, it says so.”

He then discussed he special nature of European law and the citizenship right created, drawing on a number of points made by the detailed written submissions from the People’s Challenge legal team. He explained why many EU rights would be gone forever, once Article 50 is invoked, regardless of the content of the Great Repeal Bill:

“It’s not possible for Parliament to re-enact a right to vote in the European Parliament. It is simply inconceivable. There is a statute which confers that right and Parliament simply cannot confer a right to vote for a member of the European Parliament. Inconceivable. That is one example. A second example is once we leave, assume, this is your Lordship’s question tome, assume that Working Time Directive, or other provisions are re-enacted, its quite impossible for Parliament to re -enact that my client or anybody else should have a process right, an absolutely crucial process right, to obtain a determination of the Court of Justice, in Luxembourg, as to the meaning, the scope and the meaning of that right. That will go forever. That is not possible. And it is also quite impossible for Parliament, of its own volition, to confer on my client, or anybody else, a right to free movement and all of the other fundamental rights throughout the community, free movement of services, goods, a person’s right of establishment. Parliament cannot do that of itself.”

These rights, we went on to explain, were made part of domestic law, by Parliament, under the European Communities Act 1972 and later legislation.

Lord Pannick then identified the long-established legal limits to prerogative powers, most importantly that:

“the principle of parliamentary sovereignty in the sense we are considering, is absolute. The executive cannot,without the consent of Parliament, override or take away domestic law rights which have been granted by Parliament. And the doctrine of parliamentary sovereignty is a legal doctrine. And it was described by Lord Bingham in R (Jackson) v The Attorney General, one of the foxhunting cases, as the bedrock of the constitution.”

This meant:

“…under the doctrine of parliamentary sovereignty, Parliament is the only body which, under the UK’s constitutional requirements, can take or authorise the decision to withdraw and notify under Article 50.”

He then addressed the remaining points put against his own team’s written submissions in the Government’s skeleton argument .

Lord Pannick was followed by Dominic Chambers, Mr Dos Santos’ QC who took the Court on a legal history tour of the Royal Prerogative, Parliamentary Sovereignty and Referendums, taking in landmarks such as Dicey’s 1915 Introduction to the study of the law of the Constitution which emphasises that:

“Parliament … has, under the English constitution, the right to make or unmake any law whatever and further, that no person or body is recognised by the law of England as having a right to override or set aside the legislation of Parliament.”

That ‘setting aside’, Mr Chambers argued,would unlawfully happen by executive action, were Article 50 triggered by Ministers.

He brought the Court right up to date, though,showing them the House of Lords Constitution Committee Report on Referendums, the Government’s acceptance of their non-binding nature at page 12 of its response and the briefing to Parliament on the EU Referendum Bill 2016 which was highlighted in the People’s Challenge clarification note.

The day ended with the People’s Challenge lead barrister, Helen Mountfield QC opening her case. She told the Court she was instructed by:

“…an Englishman of Bangladeshi origin, an Irishman, two Scotsmen resident in France, a Welshman and a Gibraltarian, whose wife is Spanish, with family resident in Spain.And I make that opening observation not as a start to a poor joke,but because that illustrates the nature of the EU citizenship rights which they enjoy and they seek to enjoy, which include, for example,the right, if one resides abroad within the EU, to be accompanied by third country nationals, exercising derived rights out of the citizen’s directive. So they are all beneficiaries of the EU citizenship rights. And they are all concerned to ensure that there is proper democratic authority for and scrutiny of, Britain’s future relationship with Europe and they have been funded by over 4,400 people, who have supported them through a crowd funding initiative.”

On Monday, Helen will develop the case further on seven key points.

First, notification to the European Council of a binding decision to leave the EU will remove the directly applicable or effective EU citizenship rights of UK citizens after expiry of the notification period.

Secondly, once such a binding decision to leave the EU has been notified, the status of EU citizenship for UK citizens cannot be preserved or retained by Parliament – the Great Repeal Bill, for instance, cannot replace the EU citizenship rights every UK citizen will have lost.

Thirdly, directly applicable or effective EU citizenship rights have a fundamental constitutional character because they confer wide-ranging directly enforceable rights and remedies on EU citizens, as subjects of the EU legal order (and inform the content of the common law and the interpretation of statutes).

Fourthly, the availability of such individual citizens’ rights in the law of the UK is recognised by the courts because it has been mandated by legislation.

Fifthly, for a Minster of the Crown to take a step, which will make those rights unavailable without prior Parliamentary authority, dispenses with the law or the execution of the law and is contrary to the Bill of Rights 1688.

Sixthly, that step would be contrary to the Acts of Union with Scotland because it alters the public and private law rights of those subject to Scots law which arise from their EU citizenship, without Parliamentary authority.

Last, she will argue that even if all of this were wring and the prerogative powers of the Crown were to extend to removing such rights in theory, for such powers to be used to remove rights which underpin the devolution statutes would be an unlawful exercise of the prerogative, because it would remove limitations on the powers of the devolved legislatures and assemblies to intrude upon the public and private law rights of EU citizens, which limitations underpin the constitutional settlement between the nations of the UK and the understanding of Parliament in passing the devolution legislation.