High court hears challenge to Theresa May’s plan to start process of leaving EU under article 50 without vote in parliament

This article is more than 3 years old

This article is more than 3 years old

The government does not have legal authority to use royal prerogative powers to trigger Brexit without parliamentary approval, the high court has been told.



In opening arguments over who should initiate the UK’s departure from the EU, Lord Pannick QC, who represents the lead challenger in the claim, Gina Miller, said formal notification by ministers alone would undermine parliament and “deprive people of their statutory rights”.

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Three of the most senior judges – the lord chief justice, Lord Thomas of Cwmgiedd, the master of the rolls, Sir Terence Etherton, and Lord Justice Sales – are hearing the challenge, which could have far-reaching political and constitutional effects.

At issue is who has the power to give the EU formal notification of the UK’s intention to leave under article 50 of the treaty on European Union.

“Notification,” Pannick said, “is pulling the trigger and once pulled the bullet hits the target. It inevitably leads to the consequence that the [European Communities Act 1972] ceases to apply.

“This is not simply action on the international plane … It leads to the removal of a whole series of important rights whatever parliament may think about it later.”

He added: “Prerogative powers may not be used by the minister [David Davis, the Brexit secretary] to remove rights established by the act of parliament.”

The case, Pannick said, raised questions of “fundamental constitutional importance [about] the limits of the power of the executive”.

Pannick also listed what he said the case was not about. “This court,” he explained, “is not concerned with the political wisdom of withdrawal” from the EU.

The government, he said, was also wrong to suggest that the legal challenge “was merely camouflage” to prevent Brexit.

“Mrs Miller,” Pannick said, “is entitled to require that the steps that will be taken must be taken in a lawful manner.”

The lord chief justice asked whether once article 50 had been invoked it could be stopped and whether some form of “conditional notice” could be given.

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Pannick said there was no possibility of the UK either giving conditional notification or stopping it once it had been started.

But the question of the “reversibility” of article 50 surfaced again in the afternoon, and the lord chief justice asked for further clarification of the procedure.

Helen Mountfield QC, who represents the crowd-funded People’s Challenge, said: “There’s no authority [for reversing a decision to leave the EU] because it’s never been attempted before. Reversibility is a question of interpretation of EU law.” None of the parties in the case are so far suggesting that departure is anything other than a one-way street.



Mountfield added: “The constitution of our parliamentary democracy, unwritten as it is, is predicated on the sovereignty of parliament and the courts working as an arbiter. Notification of withdrawal inevitably leads to the removal of the rights of UK citizens, whatever they may be.”



Dominic Chambers QC, who represents the second claimant, Dier dos Santos, told the court: “The referendum did not replace the [UK’s] system of parliamentary representative democracy.”

For the government to trigger article 50, he said, it would be setting itself up as a “de facto legislature”, saying that “without consulting you we have set in train an unstoppable process of leaving the EU … This is a case about what is legally required, not what is legally expedient.”



The government’s lawyers will present their arguments on Monday.

Both the Scottish and Welsh devolved governments have employed barristers to keep a “watching brief” on the hearing.

It is possible they could intervene at a later stage if, as anticipated, the case is appealed to the supreme court.

The public gallery in court four and all the court’s benches were packed. A video link to two other courts provided extra room for those eager to watch proceedings.

Outside the royal courts of justice, supporters of the claimants were draped in EU flags. Opponents handed out leaflets saying: “Invoke article 50 now.”

The hearing continues.