Parliament will gain new and extensive controls over the conduct of foreign policy if the supreme court rejects ministers’ right to use the royal prerogative to trigger Brexit, a government lawyer has told judges.
Addressing the 11 justices on the second day of the article 50 hearing, James Eadie QC denied that the government was seeking to undermine parliamentary sovereignty.
Eadie said the ruling by the high court last month – that parliament alone has legitimate authority to give notice under article 50 of the treaty on European Union of the UK’s withdrawal from the EU – would have damaging consequences.
“The reasoning of the conclusion of the [high] court has the most serious implications for the long-established use of the [government’s] foreign affairs prerogative,” Eadie said.
If the high court’s judgment against the government stands, Eadie alleged, then a new restriction on the government’s executive freedom in foreign affairs will have been created.
“It would introduce a much more stringent stream of control [by parliament through] a newly discovered principle,” Eadie said. “You would need primary legislation [to sign international treaties or other overseas developments].”
Turning to government plans for passing legislation for triggering Brexit through parliament, if it loses the supreme court case, Eadie said that it would involve a “one-line act”. The act would not provide any further detail or insight into the way the government intends to develop its negotiations with the EU, Eadie said.
Lord Keen, the Westminster government’s advocate general for Scotland, said that triggering article 50 would not damage the existing devolution architecture of the UK. “It’s perfectly clear that the matter of foreign relationships, foreign affairs and our relationship with the EU is not within the competence of the devolved legislatures,” he said.
He was addressing the supreme court before representations from Welsh and Scottish government lawyers, who will argue that under the Sewel convention the Westminster government cannot alter the rights of the citizens in the devolved nations without parliamentary assent and the assent of the devolved legislatures.
The role of the government’s great repeal bill came up at the start of the day’s hearing. “It’s valuable to know that it has no great legal significance,” Lord Sumption, one of the justices, said.
Lord Wilson, another justice, intervened: “So you say it’s irrelevant?”
Eadie, for the government, initially agreed but then said it was significant in as much as parliament was involved in debating Brexit.
“You have given two diametrically opposed answers to the same question,” Sumption said. “We shall have to work out which one you accept.”
The hearing continues.
