IT’S been perfectly plain for years now that the biggest problem facing the Scottish Conservatives is not the SNP but Boris Johnson.

Many Scots Tories recognised the existential danger he posed to them long before he became leader; how he threatened catastrophic climate change in Scottish politics by pushing centre ground voters towards the SNP and independence in a way that could prove irreversible.

As the entitled posh boy to Nicola Sturgeon’s diligent working class lawyer, he would make the First Minister shine, they despaired.

And so he has. “Operation Arse” was famously formed by a group of Scottish Tories in 2018 to try and prevent the-then foreign secretary being elected as Tory leader but it was in vain. Conservative party members, most of them in English constituencies, were too far gone by then. Intoxicated by Brexit and the Daily Mail, they gave “Boris” their resounding endorsement.

And so the Scottish Conservatives are living with a political migraine that has so far resisted all treatment.

In Scotland, the magnitude of Boris Johnson’s unpopularity is almost heroic. The latest YouGov poll at the end of October showed 78 per cent of people thought he was doing badly as Prime Minister – and that was before the sleaze scandal.

READ MORE: REBECCA McQUILLAN: EU trade war would be UK's fault

Which brings us to Andrew Bowie and his resignation as the vice chairman of the Conservative Party. Sources deny that Bowie, the MP for West Aberdeenshire, resigned from his party role this week because of the debacle engulfing his party, but the timing of his request to leave and the fact he has a majority of only 843, tell a different story.

If he fears losing his seat, it’s no surprise: Tory support is sliding.

To make matters considerably worse, Mr Bowie was among four hapless Scottish Conservatives who voted for the motion last week to trash the MPs’ standards process, only for the government to make a humiliating u-turn after the damage to MPs’ reputations had been done.

Voters in these MPs’ constituencies may well ask why they obeyed the whip when 13 of their Tory colleagues did not. Even so, it’s only fair to recognise that all parties rely on internal discipline to be effective. MPs have a pact of trust with their party leaders and this lot were badly let down. No wonder there have been so many anonymous briefings from angry Tories in the last seven days.

But is that it? Are quiet resignations and off-the-record briefings as far as they’ll go? If disgruntled Scottish Tories want credit for being brave and principled, they must be seen to be brave and principled – by openly disavowing Boris Johnson.

Admittedly, on one level it seems absurd of any Conservative MP to try and distance themselves from Mr Johnson now, as if having only just discovered his loose relationship with ethics. They campaigned on his ticket at the 2019 election, after he’d dissembled about the impacts of a no-deal Brexit and misled the Queen about proroguing parliament.

But they are still entitled to say enough is enough. In Scotland, where Boris Johnson is less popular than a cloud of midges, loyalty could cost them.

It’s usually an article of faith among politicians that splits within parties are bad for business, but that does not apply here, not when the Prime Minister is so clearly at fault.

It did Holyrood leader Douglas Ross no harm when he resigned his post as Scotland Office minister 18 months ago in protest at Dominic Cummings’ trip to Barnard Castle – for which Cummings had the backing of the PM.

READ MORE: REBECCA McQUILLAN: Affair shows Tory contempt for rules

One option for the Scottish Tories is to make themselves independent of the UK party, an idea that was last given a serious airing when Mr Johnson took over as Prime Minister. But that idea has repeatedly foundered on the grounds that it would undermine Tory attempts to campaign against independence and put Scottish Tory MPs in an impossible position. It’s a debate for another day.

For now, the Scottish Conservatives have a balder question to answer: are they prepared to say what they really think about their leader? Because if they did, they might find it was their redemption.

The headache certainly isn’t going away. The Owen Paterson affair has now prompted a parliamentary pond-dipping exercise by the media and opposition that is pulling up more and more murky material about the second jobs, mainly of Tory MPs.

Just when we thought we’d reached the nadir on Wednesday with the cringey spectacle of a British Prime Minister insisting in front of the world’s press that the UK was “not remotely a corrupt country”, hard-working second jobber Geoffrey Cox QC provided a new chapter in the saga.

Cox, a self-described “senior and distinguished professional”, is being portrayed as an ego-mountain set amid rolling foothills of complacency, topped with swirling clouds of aviation fumes. The former attorney general is thought to have made six million quid from his second job since becoming an MP.

On Wednesday, he struck back hard against critics of his legal work in the tax haven of the British Virgin Islands, stressing that his Devon constituents were of “primary importance”, only for The Mirror to allege that he was 6,000 miles away this week on Mauritius.

All within the rules, it has to be said, although questions remain about the use of his MP’s office for legal meetings. But it looks bad and speaks to a growing sense, one now increasingly entrenched in public perceptions, that the Tories are so compromised they can’t recognise unethical behaviour when they see it.

Boris Johnson could weather this storm, if no further allegations of wrongdoing emerge, but it’s become a serious crisis for his premiership. For the first time, it also opens up an intriguing new possibility: that the end of Mr Johnson’s tenure in Downing Street might come, not at the next election, but at the hands of his own colleagues.

We’re a long way from that yet. No matter how fed up they are, most Tory MPs will instinctively fear that if Mr Johnson goes down, they’ll go down with him. But in Scotland, where Mr Johnson is already so unpopular, the calculus is different. In Scotland, where Conservative MPs are still an endangered species, there’s honour to be had in standing up and speaking the truth – if they dare.

Subscribe now

We want to bring you the best The Herald has to offer every day. For just £2 for two months, you can instantly read your favourite writers including Rebecca McQuillan, Rosemary Goring, Neil Mackay, Alison Rowat, Lesely Riddoch, David leask, Hugh MacDonald, Mark Smith, Iain Macwhirter, Kevin McKenna, as well as Rab McNeil, and the (in)famous Herald Diary.

Subscribe to The Herald and don't miss a single word from your favourite writers by clicking here