IT wasn’t in the Trump stakes. There was no “fire and fury” or “locked and loaded”. But Brexit minister Michael Russell didn’t stint on the rhetoric when Theresa May’s deputy came to town on Wednesday. Damian Green’s visit was heralded by a torrent of excitable verbiage.

The UK Government, through that infernal instrument, the EU (Withdrawal) Bill, was making a “direct threat to the devolution settlement”. This “attempted power grab” must end. And that was before the First Secretary of State even entered the building. After he left, things really got cooking. Mr Russell declared the Bill “unworkable”. No longer an attempted power grab, it was now a “blatant” one. Without “serious and substantial changes”, Holyrood would withhold its consent and the PM would have a constitutional crisis on her hands. Phew!

To be fair to Mr Russell, the Fringe is on, am dram is in the air and it can be contagious. Style aside, there is also a cold hard fact involved. Section 11 of the Bill says all powers currently exercised in Brussels will be repatriated to Westminster at the point of Brexit, even those in devolved policy areas such as agriculture, fishing and the environment.

The Scottish Government says 111 devolved policy areas are involved, and most rightfully belong at Holyrood, not hoarded at Westminster. Hence the accusation of a power grab and the demand for Section 11 to be excised or drastically rewritten.

As the member state leaving the EU, the UK is inevitably the first port of call for repatriated powers. The big question is what happens next. The UK and Scottish governments agree some powers should be exercised UK-wide in “common frameworks” to avoid disrupting the UK internal market. No point causing grief to manufacturers and shoppers with separate food labelling regimes across the border, for instance.

Just how many of the 111 end up in common frameworks and how many are “released” to Holyrood, and at what speed, will now be the focus of months of talks between Mr Green, Mr Russell and the deputy FM John Swinney. Will it end in Mr Russell’s brimstone-tinted vision of anguished MSPs rejecting the Bill and then being overruled by Westminster, plunging devolution into chaos? The mild-mannered Mr Green thought not.

Setting out his position after the introductory meeting, he stressed the UK would only hold the returned powers “temporarily”. If the talks went well, powers could be identified for release to Holyrood “one day after Brexit”. Logic and common interests pointed to a deal.

But what about Section 11? It’s so integral to the Bill that it can’t be deleted or revised out of recognition. Doesn’t its presence mean a constitutional clash is nigh? Again, the UK government thinks not. In private, Whitehall insiders believe the SNP is using Section 11 as a pretext for stalling, a fake red line ministers are huffing and puffing about now in order to extract concessions later. After all, the SNP agree some common frameworks are needed, and these would flow from Section 11. How can it be for the first, yet against the second?

The assumption is that, while it might be striking an ideological pose for the Yes movement, the Scottish Government is actually far more interested in shaping the common frameworks. In particular, it wants to win the consult / consent argument. Will it merely be consulted (ie told) about the frameworks, or will it be deeply involved and have to give consent?

Hence Mr Green’s sangfroid about all the rhetoric raining down from Calton Hill. Mr Swinney and Mr Russell can have their fun with the quiet cop, shouty cop routine, but at the end of the day, both sides recognise there’s serious business to be done and want to get on.

So far, so grown up. But there’s a snag. It’s not a simple bilateral discussion. The EU is also in the mix. It may not be at the table, but its influence is ever present. There is a reluctance across Whitehall to nail anything down much in advance of Brexit, including the redistribution of repatriated powers, in case the EU takes an interest and things have to change.

The UK government isn’t inviting Europe to stick its oar in, but nor does it want to limit its bargaining options by making final decisions too soon. Scotland is a wheel within a wheel. It means that, despite Mr Green’s logic pointing to agreement with Edinburgh, a lot of UK Government decisions will go down to the wire. It will be a late and messy process. If the offer on new powers is still intolerably vague when Holyrood votes on the Bill, it may be hard to avoid rejection. Neither side wants a constitutional crisis, but Brexit may yet provide it.