Every now and again the European Parliament takes a strop, puts its foot down, makes a fuss. It might - just might - do so over Brexit; and it might - just might - use Holyrood as an excuse.

MEPs, after all, have a final say on whatever deal Britain and the European Union come to over the coming months. They have already voted on their red lines for that agreement, such as the rights of their citizens living in the UK. Keeping Scotland and other devolved British nations happy is not one of their priorities. Far from it. But that does not mean MEPs will not latch on to, say, the Scottish Parliament refusing to pass the legislative consent motion or LCM Theresa May needs for her Great Repeal Bill.

Last week I asked politicians from across the continent whether they would sign off on a deal if Holyrood had withheld an LCM. Wiley old MEPs shrugged and twinkled their eyes, revelling in the intrigue. They know, constitutionally, that the European Union can only negotiate with a member state. But they also know a potential political level to pull when they see it. Don't get me wrong: many MEPs are sympathetic to Scots being pulled, as they see it, out of the European family against their will. But they have their own political priorities. So they'll only cite Holyrood and the LCM if it suits them.

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Scotland's longest-serving member of the European Parliament, David Martin, explained. "On a legal level the LCM makes no difference at all. But politically it cold have a serious impact in terms of people's approach.

"At the end of the day we have to say yes or no. There will be all sorts of factors about whether the parliament about that. Eastern Europeans will be looking at the budget settlement. Poles will be looking at free movement.

"The Irish might take a particular interest if Scotland is unhappy.

"One of the things I keep saying to people, including government ministers who don't always seem to understand the dynamics here, is that at the end of every parliament, MEPs tends to take something prisoner, just to show we matter. What better thing for the parliament to take prisoner. Although an internal British constitutional wrangle, the LCM is the sort of thing people might pick up as a reason, as a justification.

"No, we can't support this and it not even supported in the UK. Wales is against it, Scotland is against it, Northern Ireland is against it.' You can see it feeding in to a narrative if you are looking in to an excuse to reject the package."

So what should Scottish politicians do? Should they torpedo the LCM in the hope it gives ammo to potential allies in Strasbourg and Brussels?

The SNP's Alyn Smith MEP, taking coffee with Mr Martin in Strasbourg, admits that is not an easy question. "So much of this debate is stymied because the answer to everything, honestly, is 'we don't know yet', which is hugely frustrating.

"If Holyrood was going to withhold consent, Westminster would find a way to make that consent unnecessary," he said in Strasbourg. But political arguments here and at home would be significant." Mr Smith reckons the time has come for Remainers north of the border to put on a joint front. He said: "Holyrood is descending in to a tribalism that is unhelpful. That is why we have taken the prospects of indyref2 off the table

"We have just gone through a Westminster election where the Tories were able to talk about a hypothetical referendum which is not happening and distract from the consequences of one that has. Let's reset the whole discussion." The task of Scottish Remainers? To constantly remind European partners that they still exist.