Usually when a broadcaster airs vox pops on politics, they endeavour to make sure that the samples offer a balanced display of public opinion. But when Sophy Ridge took to the streets of Edinburgh for Sky News earlier this month to survey local opinion on Boris Johnson, there was little in the way of variety on offer.

The comments from members of the public ranged from a Johnson premiership looking “quite scary” to being “incredibly divisive”. The highest praise was from a woman who thought he would “get us through Brexit” – before adding that she thought he was a “bit of a clown” generally. As Ridge summed up: “I’ll be honest, here in Edinburgh, it’s been hard to find anyone with a good word to say about Boris Johnson.” Perhaps that’s unsurprising when Johnson has a negative net approval rating of minus 37 in Scotland – the Brexit party’s Nigel Farage is more popular, on a mere minus 24. That same Panelbase survey found that more than half of Scottish voters could back independence if Johnson became prime minister.

Expect projects linking Scotland to the rest of UK rather than a personality-led drive north of the border

Reservations about Johnson aren’t just limited to the public at large – there are plenty of critics in the Tory party. A group of Scottish Tory MPs formed “Operation Arse” – a covert campaign to persuade others to vote against him in any leadership contest over fears that he would be electorally toxic in Scotland. That obviously failed. Now Johnson looks a certainty for No 10, he’s going to have to face up to his Scotland problem.

At the weekend Johnson went on a pro-union media blitz. In a Mail on Sunday column, he attempted to play up his unionist credentials by pledging to change the prime minister’s official title to add “Minister for the Union”. On the damage leaving the European Union could do, he said: “Properly done, Brexit will not threaten the union.” A Jeremy Hunt ally says: “It shows they are worried. One out of every six members are in Scotland, so they had to do something.”

It’s certainly true that Hunt has made inroads with the Scottish Conservative membership. Johnson is a grassroots favourite, but his rival is expected to fare better in Scotland. While Hunt made Aberdeen one of his first ports of call when the membership campaign kicked off, Johnson is yet to visit Scotland. A planned visit to Dumfries and Galloway over the weekend was cancelled over time issues. The Johnson camp insists he will spend a substantial amount of time there before the campaign ends.

So, what of the reception that awaits him? Ruth Davidson – the leader of the Scottish Conservatives credited with masterminding the party’s resurgence in Scotland – is strongly critical. She went so far as to block him from appearing at their annual party conference earlier this year. In May, there was speculation that she was softening her opposition to Johnson after she used an interview to say in reference to him that she will “work with whoever the prime minister is”. At the time she was criticised by Nicola Sturgeon for flip-flopping. Since then, she has taken on a more critical tone – endorsing Sajid Javid and now Hunt.

This suggests she thinks that the best way to deal with a Prime Minister Johnson is to do so reluctantly. While Johnson has a handful of Scottish Conservative MPs actively campaigning for him, the bulk are unenthusiastic, and still working out how best to handle an undesirable scenario.

That they find a way to work with Johnson is crucial to the future of the Tory party. While the Scottish Tories were once on the brink of extinction, the main party now relies on them for power. In the 2017 snap election, Davidson’s success pitching the Scottish Conservatives as the party of the union saw the party enjoy its best performance in the country since 1983, winning 13 seats. Nine of those have majorities below 5,000. Worried over the health of the party in a general election, one Scottish Tory has inquired about getting an English seat but has since decided to fight it out.

In any election, these seats are key to the Tories holding on to power, let alone winning a majority. Already the SNP has shown how it will capitalise on a Prime Minister Johnson on this. For two weeks the leader of the party’s Westminster group, Ian Blackford, has used PMQs to launch personal attacks on Johnson – accusing him of being both a racist and a serial liar. If Johnson becomes PM, this strategy will only grow.

The hope is that Johnson could be good news in Scotland so long as the relationship is not too cosy. Scottish Tories think that, rather than mass visits to try to endear himself to the voters, Johnson’s love of big infrastructure promises and desire to be liked will lead to practical achievements they can sell on the doorstep. Expect projects linking Scotland to the rest of UK rather than a personality-led drive north of the border.

For Johnson’s problem isn’t simply Brexit, some say his personality is just as toxic – they complain that an Old Etonian British eccentric plays badly with Scottish voters. Whatever happens with Brexit under a Johnson premiership, Davidson and the Scottish Conservative MPs are likely to remain some of his fiercest critics. But if they can strike the right balance between political distance and co-operation on strengthening the union, there could be hope for a Johnson premiership yet.

• Katy Balls is the Spectator’s deputy political editor