The British government appealed to the Supreme Court on Tuesday to rule on whether Brexit bills passed last month by the Scottish and Welsh parliaments were constitutionally sound, arguing that they would cause legal confusion.
The legislatures in Edinburgh and Cardiff passed the bills to try to ensure they keep all their current powers after Britain leaves the European Union, arguing that the national parliament's own Brexit legislation risked eroding those powers.
The central government's referral to the Supreme Court, which implies that London thinks Edinburgh and Cardiff may have gone beyond their devolved powers in passing their Brexit bills, represents an escalation of an already thorny dispute.
The government in London says the Scottish and Welsh bills cover similar ground to legislation currently going through the national parliament, but with significant differences.
"This legislation risks creating serious legal uncertainty for individuals and businesses as we leave the EU," Attorney General Jeremy Wright, the UK government's chief lawyer, said in a statement.
He said the referral to the Supreme Court was a protective measure in the public interest, and he hoped the issue would be resolved without the need to continue with the litigation.
The Scottish government, run by the Scottish National Party (SNP) which fiercely opposes the Conservative Party in power in London, said it was satisfied that the bill passed in the Edinburgh parliament was within legislative competence.
"Our Continuity Bill is an important and necessary piece of legislation to prepare Scotland's laws for Brexit while protecting the powers of the Scottish parliament that people voted for," said Scottish Brexit minister Michael Russell.
Powers which are currently devolved to Edinburgh and Cardiff, such as over agriculture, fisheries and food standards and labelling - administered at the moment from Brussels because they fall within EU frameworks - will come back to the national parliament once Britain leaves the EU.
Edinburgh and Cardiff accuse the British government of what they call a power-grab to keep those powers in London, and are pressing for changes to the Brexit legislation going through the national parliament to prevent that from happening.
Should they not secure those changes, the bills passed last month are intended to act as a backstop.
The central government denies any power grab is afoot.
Russell said the SNP government would argue at the Supreme Court that "it is within the powers of the Scottish parliament to prepare for the consequences for devolved matters of UK withdrawal from the European Union".
An SNP lawmaker denounced the referral to the Supreme Court as interference by the Conservatives, or Tories.
"Scotland's parliament made its voice clear, passing the bill by 95 votes to 32. And yet, the Tories still, arrogantly, think they alone have the right to strike it down," said Ivan McKee. REUTERS SDR 1556
-- (Reuters) -- C-1-1-DL0431-1331422.Xml