WHITEHALL is bracing itself for a potential constitutional battle with Holyrood over the forthcoming Great Repeal Bill, which will transfer all European law into UK regulation, as part of the Brexit process.

The new legislation, announced in October, and which will be included in the Queen’s Speech in May, will end the EU's legal supremacy in the UK by converting all EU requirements into British law as soon as Brexit happens.

The legislation will end the jurisdiction of the European Court of Justice in the UK.

Read more: Mundell dismisses SNP Brexit plan ahead of Whitehall showdown

As EU laws are debated by MPs and peers it is likely there will be a large number of requests for changes depending on how the negotiations play out.

Michael Russell, the Scottish Government’s minister engaged in the talks with the UK Government over Brexit, has already suggested Holyrood could vote against the bill.

The legislation transposing all EU law applying to the UK into domestic law could implement a range of provisions that are within the competence of the Scottish Parliament such as agriculture and thus require the consent of the Scottish Parliament.

This process could involve the requirement of a number of legislative consent motions. But this opens up the possibility that MSPs could withhold consent if they disagreed with any proposed changes.

Read more: Mundell dismisses SNP Brexit plan ahead of Whitehall showdown

One senior Whitehall source noted: “This could become very complicated and there could be a clash with Holyrood.”

A Commons briefing paper on the subject notes: “If any delegated powers in the bill enabled UK Ministers to legislate in regard to devolved matters there would be concerns from the devolved governments and legislatures that the Sewel process might be circumvented.”

During PMQs, Theresa May admitted some elements of the bill could be subject to the controversial principle of English Votes for English laws[Evel], which bans Scottish MPs from voting on certain parts of legislation deemed England-only.

Asked by Kirsty Blackman, the SNP MP for Aberdeen North, to ensure no part of the bill would be subject to Evel, the Prime Minister admitted the legislation would have a number of “complex issues,” one of which would be how to deal with reserved and devolved matters.

Read more: Mundell dismisses SNP Brexit plan ahead of Whitehall showdown

But she made clear: "Any legislation brought before this House, if any part of it only applies to England, then it will be subject to the English votes on English laws."