THE UK Government has mounted an unprecedented legal bid against Scotland's alternative Brexit Bill, challenging the legislation in the Supreme Court.

The Scottish Parliament's Continuity Bill aims to protect powers in devolved areas returning to the UK after Brexit amid an attempted power grab by Theresa May's government.

There are 111 powers and responsibilities due to be repatriated, but intense negotiations have failed to find agreement on around 24 of those.

Attorney General Jeremy Wright and the Advocate General, Lord Keen of Elie, Whitehall's senior Scottish lawyer, will seek to establish the legality of Scotland's Brexit Bill – asking the court whether it is constitutional and within devolved powers.

Holyrood's Presiding Officer Ken Macintosh has said the Bill is not within the Scottish Parliament's competence, but the legislation was introduced following advice from Lord Advocate James Wolffe.

Attorney General Jeremy Wright QC MP said: "This legislation risks creating serious legal uncertainty for individuals and businesses as we leave the EU.

"This reference is a protective measure which we are taking in the public interest.

"The Government very much hopes this issue will be resolved without the need to continue with this litigation."

Ministers in both Cardiff and Edinburgh have repeatedly branded the UK Government's EU Withdrawal Bill a "power grab" which threatens devolution.

SNP MSP Ivan McKee MSP, who sits on Holyrood’s Constitution Committee which considered the Continuity Bill, said: “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.

“The Tories have no mandate but think they can do whatever they want to Scotland and get away with it – and this legal challenge proves it.

“They opposed devolution in the first place, they’ve consistently voted against Scotland’s interests and now they want to clip Holyrood’s wings once again."

The alternative Brexit Bill in Wales will also be challenged by the UK.