THERESA May’s Tory Government are set to use all-powerful, non-accountable, Tudor-era measures to decide which responsibilities Holyrood can and cannot be trusted with, Scotland’s Brexit Secretary has warned.

Speaking on the BBC’s Sunday Politics Scotland yesterday, Michael Russell said he believed the UK Government would use the so-called Henry VIII powers, granted to them by the Repeal Bill, to bypass the Scottish Parliament and allow Whitehall to pick and choose what should be repatriated from Brussels to Edinburgh. Tory Scotland Office minister Ian Duncan denied this, accusing the SNP of brinkmanship.

The Henry VIII powers, or delegated powers, are ostensibly to speed up the process of Brexit, allowing ministers to make sweeping changes without having to go through the whole parliamentary process.

The Bill, published last week, is effectively designed to change all EU law into British law so that the same rules apply on the day of Brexit as the day before. Ministers will have two years to amend more than 12,000 EU regulations, and have already identified between 800 and 1000 amendments that are needed.

But opponents are worried the Government may be overreaching themselves by using the power.

Russell said it was going to lead to “constitutional crisis”, with Tory ministers being able to change the laws of Scotland by decree and without any accountability.

When asked outright if he was concerned that the UK Government would use “these so-called Henry VIII powers” to decide what was devolved and what was not, Russell said: “Of course, that is what they are intending to do.”

The Brexit Secretary said he and his department had seen a draft of the Repeal Bill two weeks ago.

“The normal thing for a Bill of this nature would be that officials would work together over a long period of time to get it right because it affects Scotland so much,” Russell said.

The minister added: “Up until now there is a list of things that are devolved and a list of things that are reserved. Now there will be areas which are neither, or both, and decisions will be made by UK ministers without consulting the Scottish Parliament and Scottish Government on matters which are actually devolved. That is unacceptable and it would lead to chaos.”

Duncan, the former MEP who was made a Lord and appointed to the Scotland Office last month, told the programme: “What we are talking about in this interim period is a transition period.”

He added “These powers will be used to determine what should be part of a common framework, replacing the common framework of the EU, and that should be done through an agreement between each of the particular powers moving forward.

“There will also be elements that go straight back to Scotland, to Wales, to Northern Ireland because they do not fit into a necessary component of a common framework.”

Duncan added that if the Scottish Parliament voted against granting consent for the Repeal Bill it would cause significant difficulties and if the Scottish Government engaged in brinkmanship it would put people in jeopardy.

He said: “The First Minister will have to explain to them exactly what’s she’s going to do instead of that. It’s not good enough simply to posture.

“You need to be able to say to people who are going to be affected on the day after Brexit that they will be able to go forward and continue to do business as they do now.”

Duncan added: “I think right now we would have significant difficulties in the body politic in Scotland if there’s no certainty of what laws will apply to Scotland after a particular Brexit moment ... I suspect at that point there would be serious implications.”

Meanwhile, former top civil servant Gus O’Donnell warned May that her Government is woefully under- prepared for the work needed for Brexit. Writing in the Observer, he calls on ministers to “start being honest about the complexity of the challenge.

“There is no chance all the details will be hammered out in 20 months,” he warned, calling for a long transition phase.