BREXIT COURT CASE: Government says Parliament shouldn't get Article 50 vote because it has failed to 'stand up for itself'
Attorney General Jeremy Wright QC argued that MPs "knew what triggering Article 50 would mean" when it passed the referendum legislation but "took no step, made no provision, imposed no restrictions" on the government's right to use the royal prerogative.
He added: "If this [claim] is all about standing up for parliament then I say parliament can stand up for itself."
The High Court ruled last month that May must pass an act of parliament before triggering Britain's exit from the European Union. The government opted to appeal the decision and is now relying on Wright and a team of lawyers to persuade the UK's highest court to overrule the High Court's decision and let May bypass parliament before triggering Article 50 of the Lisbon Treaty.
The courtroom was packed to hear the opening day of the appeal. A long queue of people snaked around the Westminster building hours before proceedings got underway on Monday morning, while protestors from both the pro-EU and pro-Brexit camps held signs and banners aloft outside.
In his opening remarks, Wright argued that MPs have had plenty of chances to limit the royal prerogative powers in the past, including when it voted on whether to pass the original EU referendum bill. "Parliament is sovereign and can legislate to limit the prerogative," he said.
"But where it has done it has been done sparingly. Parliament has considered its involvement in the making of treaties. Parliament has also considered with care and in great detail what the balance of parliamentary sovereignty and prerogative powers in relation to the EU should be."
Wright and Jamie Eadie QC also focused on the issue of "dualism" and how it is commonplace for the UK government to act without parliamentary approval when it comes to international treaties.
Eadie argued: "Prerogative powers may be exercised to create international legal effects on the international plain. When it makes an international treaty it binds the UK to an international agreement using prerogative powers.
"The use of royal prerogative for international treaties is sound not suspect - and subject to parliamentary restriction where parliament chooses to do so."
In effect, Wright and Eadie argued that Britain's membership of the EU is a form of international treaty and, as a consequence, the government has the constitutional right to take action on this treaty by exercising the royal prerogative.
They also argued that although EU law has been transposed into domestic law, this does not limit the actions of the government on an international level. This is significant because the High Court ruled that bypassing parliament before triggering Article 50 would be unlawful as it would lead to rights enjoyed by Brits as EU citizens being destroyed in an instant.
Eadie's submission was abruptly interrupted by Lord Carnwath, who suggested that the logic of the government's case means that the prime minister could have triggered Article 50 without the or parliamentary approval or even the mandate of a referendum result.