THE UK government is trying to commandeer more than 100 policy areas that ought to be controlled by Holyrood, the SNP’s Brexit minister has claimed.

Ahead of a meeting between the UK and Scottish governments, Michael Russell said the attempted power grab represented a “direct threat to the devolution settlement”.

Mr Russell and deputy First Minister John Swinney will to discuss post-Brexit powers with Scottish Secretary David Mundell and First Secretary Damian Green in Edinburgh today.

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Under the UK government’s EU (Withdrawal) Bill, all powers currently exercised by the EU would revert to Westminster in March 2019, even those in devolved areas such as fishing, agriculture and the environment.

The SNP has previously argued all devolved powers should go to Holyrood by default.

However Downing Street wants to discuss which powers are best devolved and which subject to cross-border “framework agreements” to maintain the UK's internal market.

Mr Russell said he would tell Mr Green, who is effectively deputy Prime Minister, that powers repatriated from Brussels must not bypass Holyrood only to sit at Westminster.

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Warning that MSPs would reject a Bill with such an outcome, creating a constitutional crisis, Mr Russell said: “We have an attempted power grab which must be abandoned. It is essential they change the EU (Withdrawal) Bill, which represents a fundamental attack on the principles of devolution.

“The Bill - as it currently stands - means that Westminster would take exclusive control over significant areas of devolved policy, such as support for Scotland’s farmers and food producers and many aspects of environmental protection and control of our seas.

“We know that the UK Government has its eye on more than 100 policy areas. That is a direct threat to the devolution settlement the people of Scotland voted for in 1997.”

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But Mr Russell also appeared to soften the SNP’s previous insistence on all powers returning to Holyrood, saying he was not opposed to some negotiated UK-wide frameworks.

He added: “Today we will make clear that changes must be made to protect devolution.

“All devolved powers carried out at an EU level must come back to the Scottish Parliament. We are not opposed in principle to UK-wide frameworks in certain areas - but this must be on the basis of agreement among equals, not imposed by Westminster.”

The UK Government said today’s talks would focus on arrangements for “distributing powers returned from the European Union” and identifying potential common frameworks.

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Mr Green said: “These are important talks. In some areas there will need to be a common approach.

"There will be other areas where I intend that the Scottish and UK Governments can make progress in identifying policy areas that could be released to Holyrood under the new legislative arrangements.

“We expect there will be a significant increase in the decision-making power of each devolved administration and we want to address this in a way which delivers certainty and continuity for people and businesses across the UK.”

Mr Mundell, who has promised a powers “bonanza” for Holyrood, added: “The Bill sets out temporary arrangements that allow us to discuss areas where we will need to take a UK-wide approach and where new decision-making powers can be released to Holyrood.”

Meanwhile, the President of the Supreme Court has said the UK Government must provide greater clarity about how UK law will evolve after Brexit, once the country is no longer bound by the rulings of the European Court of Justice.

The EU (Withdrawal) Bill says UK courts need not heed future ECJ decisions after Brexit, but may do so if they consider it “appropriate”, leading to fears of a legal hotchpotch.

Lord Neuberger said if parliament was not more explicit about what should happen it would be “unfair” for judges to be blamed for developing the law as best they could.