Top lawyers clash over whether ministers can start Brexit with royal prerogative
Top lawyers have locked horns in the Supreme Court over whether Government ministers can use the royal prerogative to trigger Brexit.
The legal battle follows a landmark High Court ruling in November that ministers do not have the prerogative powers necessary to trigger Article 50 of the Lisbon Treaty and start the two-year process of negotiating Brexit without the prior authority of Parliament.
Brexit Secretary David Davis is asking 11 Supreme Court justices - a record number to sit on any case - to rule the High Court judges erred in law.
James Eadie QC, for the Government, said their decision "cannot possibly be sustained" and international treaty-making powers under the prerogative could lawfully be used to trigger Brexit.
Mr Eadie told the justices: "It is said that the Government giving Article 50 notice is an affront to Parliamentary sovereignty because Parliament has created rights and only it can alter them,
"Our case fully respects, and offers no affront, to Parliamentary sovereignty."
He said Parliament was deeply involved in the Brexit process and opposition motions were due to be debated in the House of Commons this week.
But Lord Pannick QC disagreed and argued that "the prerogative power to enter into and terminate treaties does not allow ministers to nullify statutory rights and duties".
Lord Pannick is representing Gina Miller, an investment fund manager and philanthropist, who was the lead claimant in the group that won the historic High Court ruling blocking the use of the prerogative.
He said on Tuesday, the second day of a four-day hearing, that it would be "quite extraordinary" if the 1972 Act "could be set at nought by the actions of a minister acting without Parliamentary authority".
The QC told the court: "Parliament is sovereign. What Parliament created, only Parliament can take away."
If the case put forward by the Government was correct, he argued, it would mean that the 1972 European Communities Act - which paved the way for the UK to join the EU - would, "far from having a constitutional status", have a "lesser status" than the Dangerous Dogs Act.
Lord Pannick described the referendum which produced a clear majority in favour of leaving the EU as "plainly an event of considerable political significance".
But it was not a matter for the court "because it is irrelevant to the legal issue of whether ministers enjoy prerogative powers to set aside the 1972 Act."
Lord Keen QC, Advocate General for Scotland, told the court it was perfectly clear that the royal prerogative applied in Scotland, Wales and Northern Ireland as well as England and its use was a matter for the UK Government.
John Larkin QC, Attorney General for Northern Ireland, agreed with Lord Keen that the triggering of Article 50 by the UK Government fell within the royal prerogative.
The chief legal adviser to the Northern Ireland Executive said there is no provision in Northern Ireland legislation that "purports to limit, or has the effect of limiting, the powers of the UK Government in international affairs".
The hearing concludes on Thursday and judgment is expected in the new year.