Boris Johnson is the first to admit he is not Scottish and has no real Scottish connection, although he claims the Johnsons may have originally been Lowland Scots.

He has no political track record in Scotland, having been London Mayor and a London MP.

He did once stand to be Rector of Edinburgh University - but came third, behind former Green MSP Mark Ballard and journalist Magnus Linklater.

In his days as a journalist and a London-based politician, his comments on Scotland were sometimes less than supportive. He famously suggested that a pound spent in Croydon was worth more than a pound spent in Strathclyde. In 2009, he described the Barnett Formula as a "kind of present... from the English taxpayer".

As a result of this and her dealings with him, Scottish Conservative leader Ruth Davidson backed anyone but Boris for the leadership. Her deputy Jackson Carlaw attacked the new Prime Minister's loose use of language.

The SNP's Westminster leader Ian Blackford attacked Boris Johnson as a racist at Prime Minister's Questions last month for his previous comments about Scotland and Muslim women.

The Scottish Conservative leadership will undoubtedly lose clout with Boris Johnson as party leader and Prime Minister. Ruth Davidson does not trust him or get on with him in the way she did with Theresa May and David Cameron, and clashed with him during the 2016 EU Referendum.

She has worked hard to rebuild the reputation of the Conservatives since the 2014 Independence referendum, successfully recreating them as the protectors of the Union. Now that seems at risk.

A Panelbase poll last month suggested that Boris Johnson becoming Prime Minister could tip support for independence over 50% in Scotland.

Polling this week suggested more voters in Scotland are put off than attracted to the Conservatives if led by Boris Johnson - a lot of that stemming from his leadership of the Brexit campaign.

So what has Boris Johnson said about Scotland during the leadership campaign? Not very much.

At the Conservative party leadership Hustings in Perth, he went back on previous criticism of the Barnet formula.

"I think the Barnett formula must stay, and we must support our precious union," Johnson said.

He went on to say that his campaign announcements of funding for education and police would mean around £80m of Barnett consequentials for Scotland, which he hoped the Scottish Government would invest in those same areas.

On the union, he said he could "see no case for having a second referendum in Scotland" and promised to "put the union before Brexit". He argued a good Brexit could "entrench and intensify the Union....are the SNP going to campaign to hand back control of Scottish fishing to Brussels?"

He later told me that he would use some of the UK Government's half-billion-pound advertising budget to celebrate the union , and "set up a unit in Downing Street to stress-test and sense-test everything we do to uphold the union".

His income tax plans were less clear. Early in the leadership campaign he announced proposals to cut income tax for those earning £50,000 - £80,000, funded partly by increasing national insurance.

Since income tax is devolved, his plans would cost Scots an extra £3000 a year. In Perth, Boris Johnson promised to "work to ensure there was no such adverse consequence".

Before the hustings, Johnson visited BAE Systems on the Clyde and met young workers. He said their work was a direct result of Scotland's membership of the union, "the awesome foursome... if we weren't working together on our defence policy these investments would not be happening".

He also told me he wasn't bothered by Operation A*se - the plan hatched by Scottish Tories to stop him becoming Prime Minister in 2016. It worked then, but not now.

The leader they think will damage their party's prospects in Scotland, put the union at risk, and threaten a no-deal Brexit has the keys to Number 10 (or at least he would if it had keys, but if you look closely at the front door in Downing Street it doesn't have a keyhole).

In Scotland, Boris Johnson said his top priority was the union. Everywhere else, he says his top priority is Brexit, particularly leaving on October 31, with or without a deal, do or die.

So that is what he has to do, regardless of the risks it could pose to the UK.