Analysis: Crisis in No 10 lays bare PM's trust problem as Scotland poll looms

Boris Johnson’s appeal in Scotland, or rather the distinct lack of it, was summed up more in sorrow than anger by one senior MP: "We managed to get a few people with doubts about Boris to vote for us at the election but this Cummings affair just confirmed their original opinion."

And that view has now been amplified at least ten-fold following the resignation of Douglas Ross, as the under-secretary of state at the Scottish Office, in protest at the actions of the prime minister’s senior aide.

He said he could not in good faith tell his constituents, who could not care for their sick relatives or say goodbye to dying ones while obeying lockdown rules, that Mr Cummings had acted appropriately.

Mr Ross was not just a popular and talented politician but also one with the ability to take on and beat the Tories’ principal enemies in Scotland, Nicola Sturgeon’s SNP.

"He had an unerring skill for getting under the skin of the Nats," said one senior official.

Embarrassing as that departure was – in spite of entreaties to Mr Ross to stay from both the Prime Minister and the cause of the rift, Mr Cummings – it paled when set alongside a very public disagreement between Mr Johnson and the leader of the Scottish Conservatives, Jackson Carlaw.

With elections to the Holyrood parliament only a year away, MSPs from constituencies stretching from the Highlands to the Borders demanded Mr Cummings resignation claiming that many of their constituents were furious that having suffered the restrictions of the lockdown they saw the PM’s closest aide ignoring them.

After initially being heavily criticised for not joining in their protests, Mr Carlaw, who will lead the party into that contest, added significantly to the clamour, calling the Cummings affair a ‘distraction’ and demanding that he should ‘consider his position’ – parliamentary euphemism for resignation.

Next year’s Holyrood poll is a major yardstick not just for the Conservatives but also for the maintenance of the United Kingdom. At one time, the Scottish Tories had hoped to finish as the largest party and even, albeit in their wildest dreams, to form a minority devolved government north of the border.

But following Brexit, which two-thirds of Scots voted against, and the departure of the popular Ruth Davidson from the leadership, that ambition has long gone. Now the Tories are desperate to hang onto the creditable second place they won in 2016.

They lost half their Commons seats to the SNP in the December general election and all of their 31 Holyrood seats will be top targets for the nationalists next year.

A massive SNP victory would almost certainly help those who want to break-up Britain in a new independence referendum which Ms Sturgeon is demanding for next year. Although the Prime Minister has refused to grant permission for such a vote – following the successful Unionist victory in 2014 – a big SNP win next year would make it difficult to refuse what’s called Indyref2.

In the Tories’ favour is the fact that a bitter civil war is expected to erupt in the SNP as soon as the virus emergency is over. This follows former leader Alex Salmond’s acquittal on all charges of sexual assault in March, after which he and his allies claimed he had been the victim of a conspiracy involving a number of people in Ms Sturgeon’s ‘orbit’.

Unionists can also point to the massive benefit of being part of the UK during the present crisis. "It has been British – not Scottish - money that the government has been dishing out to help people in Scotland," said one senior Tory.

All of that said, the Scottish Tories must avoid a drubbing next year but are pretty much impotent without the financial and campaigning muscle of the UK party at election time, with the British Prime Minister expected to play a key role, just as David Cameron did six years ago. But Mr Johnson’s persona as well as his enthusiasm for Brexit has led many Tory voters, as well as undecided voters, to believe him to be a handicap rather than an asset.

That suspicion has been redoubled by the Cummings affair with many aghast that Mr Johnson was prepared to split his party and government merely to give apparently unqualified support to an unelected aide.

The undoubted anger in Scottish Tory ranks about Mr Johnson’s handling of the Cummings affair might well re-kindle support for a separate Conservative party north of the border even if it is highly unlikely in current circumstances.

It’s possible safe to say that the power wielded by Mr Cummings undoubtedly made him very unpopular with several ministers – making some kind of huge row almost inevitable.

And as one vastly experienced grandee commented: "I quite like Dom Cummings but even before all this I didn’t think he’d last beyond the summer. Anyway, these special advisors always go eventually, don’t they?"