Leaving the European Union will serve to strengthen devolution within the UK, Scottish Secretary David Mundell is to argue.
He will use a speech to mark the 20th anniversary of the establishment of the Scottish Parliament to reject claims from the Scottish Government that Brexit will “damage devolution”.
The decision to quit the EU has increased tensions between Theresa May’s Westminster Government and Nicola Sturgeon’s Edinburgh administration.
Almost two-thirds of Scots voted to Remain in 2016, with SNP ministers repeatedly accusing the UK Government of ignoring their wishes.
Ms Sturgeon, the SNP leader and First Minister, believes Scots should have another chance to vote on independence when there is more “clarity” on the impact of Brexit.
Her SNP ministers have repeatedly claimed key Brexit legislation is a “power grab”, which could see Scotland lose out on powers returning from Brussels.
But Mr Mundell will brand such claims an “invented grievance” and “complete fantasy”
In a speech in Edinburgh almost 20 years after the first Scottish Parliament election, he will insist: “I reject completely the argument put forward by opponents of devolution that it has been crushed by Brexit.”
The Scottish Tory MP – who was elected to Holyrood in the 1999 election – will add: “I do not believe Brexit will damage devolution. I want it to strengthen devolution, and I believe that can and will happen.
“Leaving the EU will bring new powers to Holyrood and new responsibilities to the Scottish Government.”
Describing himself as a “passionate supporter” of devolution, Mr Mundell will insist that two decades on from its creation, the Scottish Parliament is one of the most powerful assemblies of its kind in the world.
He will add: “To listen to the rhetoric coming from some of my political opponents, you could be forgiven for thinking that Holyrood is being stripped of a whole raft of powers it currently exercises.
“It is complete fantasy; an invented grievance. The reality is that more than 100 powers previously exercised in Brussels will transfer to Edinburgh on the day we leave the EU.
“To characterise this process as a ‘power grab’ is nonsense. We should remain deeply suspicious when opponents of devolution try to present themselves as its champions and protectors.”
Going forward he will call for the Scottish and UK governments to work together closely “for the benefit of the people of Scotland”.
Mr Mundell will say: “Scotland would be ill-served if one government cannot add to the work that is being done by another. The time is right for this.
“Scots expect their two governments to work together and politicians on all sides accept the need to work together.”
However SNP depute leader Keith Brown said: “The Tories fought tooth and nail against devolution in the first place – and their attitude has barely changed since.
“David Mundell is perfectly content with imposing a hard Brexit on Scotland against our will – while making a power grab on areas the Leave campaign pledged would come directly to Holyrood.
“After Theresa May trampled all over David Mundell’s self-declared red-lines, if he had any credibility he would have resigned months ago.”