It’s not supposed to be like this. Two years out from an election in which Ruth Davidson hopes to depose Nicola Sturgeon from the Irn-Bru throne, the opinion polls are dismal for the Scottish Tory leader.

It is, largely, down to Brexit. The collapse of the Conservatives at Westminster into various warring camps, the power vacuum in No 10, the emergence of Boris Johnson as apparent PM-in-waiting, the explosive return of Farage as the face of English right-wing nationalism – none of this is helping Davidson.

Then there’s the sense that Scotland’s wishes have been ignored, that Sturgeon’s SNP is at least uncompromised by ties to a mother party at Westminster, and that Scotland and England seem increasingly set on different tracks.

Davidson, a genuine One Nation politician who has spent years working her socks off to refresh the party’s image in a nation where the very word “Tory” was used as an insult, is very much a victim of events. It remains to be seen whether her hard-earned detoxification can withstand this onslaught.

The most recent poll for YouGov ahead of Thursday’s European election tells a stark story. The SNP, 12 years into power in Edinburgh, is on 38 per cent, which would secure the party three of Scotland’s six MEPs. Farage’s Brexit Party is second, on 20 per cent – given Scotland’s Remain bias, it is sometimes forgotten that 38 per cent of Scots voted Leave in 2016. Brexiteers north of the border are clearly as unhappy with the Conservatives of those in the rest of the UK.

Next come the Scottish Greens, on 11 per cent. Labour and the Tories are on 10 per cent each, which if replicated on Thursday would see both parties wiped out. This is not exactly the launchpad either wanted as they sets their sights on 2021. But it is Davidson who will feel the sting most cruelly.

Her return from maternity leave at the beginning of this month was intended to bring with it a surge of momentum, an injection of the charisma and energy that saw her supplant Labour as the official opposition at Holyrood in the last election in 2016. Instead, she has arrived to a headwind that threatens to blow the whole Davidson project off course.

No one doubts the Tory leader’s political nous, but the challenge presented to her by the Tories at Westminster is practically impossible.

With Boris Johnson miles ahead in the race to replace Theresa May, Davidson finds herself in a tight spot. She has no time for the former foreign secretary, debated him furiously during the Brexit referendum campaign, and is known to have supported Amber Rudd – a fellow moderate and ex-Remainer – during the last leadership contest.

If Johnson makes it to No 10, Davidson will have to sell the new PM to a profoundly suspicious Scotland, and risk looking like a hypocrite as she does so. Her aides already appear to be preparing the ground for that uncomfortable outcome.

If English nationalism drives UK politics for the next few years, both in terms of rhetoric and policy, the Union will undoubtedly feel the strain. And Davidson will be its most prominent face north of the Border.

All of it boxes her in, limiting her room for manoeuvre and dragging her into battles she would rather avoid. And there is a danger that it all drowns out whatever bold and distinctively Scottish policy platform she intends to put in front of the electorate in 2021.

She wants to target an aged SNP government that she says is tired and failing, but with the Nats still polling around 40 per cent this far into their reign, her task was already formidable. Now, hamstrung by calamity in London and her necessary accommodation with the consequences, the challenge appears all the greater.

It would be quite the irony if, in the end, it was Boris who did for Ruth.