SCOTLAND, we are told, now has the most powerful devolved Parliament anywhere in the world.

So goes the narrative of many Tory and Labour politicians. But it is a claim that is radically at odds with – and completely undermined by – the current threat to Holyrood’s powers in the form of the EU Withdrawal Bill.

If that claim to being the most powerful devolved legislature was in any way true then the Scottish Parliament would not now face the prospect of having its powers curtailed, in potentially far-reaching and as yet unforeseeable ways, by Westminster.

No one should be under any illusions about what is being proposed. Because, while the specific details of the Withdrawal Bill and its impact on devolved governments are complex, technical and in some ways quite arcane, the underlying principle at stake is actually very simple.

After Brexit, the UK Government has made clear it wants the final say on many devolved policy areas which are currently subject to EU law – completely demolishing the principle at the heart of the devolution settlement endorsed democratically by the people of Scotland more than 20 years ago.

The Tories have now proposed amendments to the Bill which they say take account of our concerns. But, as ever, the devil is in the detail, and a careful reading of the small print betrays the reality of what we are being offered.

They say that Westminster would not seek to legislate in devolved areas post-Brexit unless the issue had been subject to a so-called “consent decision” by the Scottish Parliament.

But the Conservatives then go on to give their own very particular definition of a consent motion.

It is, they say, when the Scottish Parliament has voted in favour of a motion consenting to what is proposed. Or when it has voted against such a motion. Or indeed when Holyrood decides not to lay and vote on a motion at all.

So if the Scottish Parliament says yes, it is taken as agreement, if it says no it is similarly taken as agreement – and if it does nothing at all, that too is agreement in the language of post-Brexit Toryism.

It is as surreal and perverse a definition of the word consent possibly ever to have been concocted in the English language.

That is why the Scottish Government has refused to sign up to any deal based on this mockery of consensus, which demolishes the notion of a partnership of equals.

Contrary to some claims, we have moved and been ready to give concessions since the start of this process. To begin with, if we were to agree to the bill, we would be enabling legislation whose primary purpose is to take Scotland, along with the rest of the UK, out of the EU – despite the nation’s overwhelming vote to remain, and the Scottish Government’s strong opposition to Brexit.

We have also made clear we are prepared to agree so-called common UK-wide frameworks for some devolved policy areas, but only if they are agreed by consent and not by imposition.

We have now also proposed two further routes to agreement. Either the UK Government can entirely remove Clause 11 of the Bill, which contains these provisions. Or it can agree to the Scottish Government giving a voluntary commitment not to legislate in certain areas for a period of time after Brexit, in tandem with the UK Government’s own undertaking.

The Scottish Government has been accused of being isolated for our refusal to sign up to a deal. But, as I made clear in Parliament this week, if our principled stance means the SNP are the only or the last party standing, defending the founding principles of devolution, then so be it.

But in reality, it is the Tories who have been isolated on the issue of Westminster’s power grab.

It was they – and they alone – who voted against the Continuity Bill which recently passed with the support of all the other parties and which is aimed at providing the legal clarity and certainty needed in certain areas after Brexit, should Holyrood not consent to the Withdrawal Bill. Just as it was the Tories who, alone, opposed devolution in the first place.

For Labour, the challenge is whether they are prepared to defend those founding principles of devolution, championed by Donald Dewar and backed by the people in a referendum, or alternatively are prepared to roll over and accept a Tory power grab.

And we should be under no illusions about how extensive that power grab could be – the Tory proposal would see Westminster hold the whip hand over devolved powers for a period of seven years.

Who knows what that could mean – imagine Jacob Rees-Mogg as Prime Minister, trampling all over Holyrood’s authority and rolling back devolution. Would Holyrood’s ban on GM crops be overturned? Would a trade deal with Trump’s America see us subjected to chlorinated chicken and hormone-injected beef? And would our NHS remain free of interference?

Last week Holyrood passed landmark social security legislation, paving the way for a more humane welfare system in Scotland, and this week world-leading laws on alcohol minimum pricing come into effect.

These are the ways Scotland’s national Parliament makes a positive difference to people’s lives and, 20 years on from the Act which established it, it is now time for everyone who believes in our Parliament to defend it.