The former foreign secretary has approached a number of Scottish Tories to canvas their support, with growing pressure on Theresa May to stand down this summer.
But with Johnson battling negative ratings north of the border, he has been told that only Ruth Davidson can boost Conservative fortunes in Scotland and hold on to the 13 MPs won by the party in a dramatic breakthrough two years ago.
Instead, Michael Gove is emerging as the preferred candidate of Scottish Conservatives, with one source saying many of the party’s MPs would swing behind him because he “gets the Union”.
Eight of the Conservatives’ 13 Scottish seats were won with a majority of less than 10 per cent. A YouGov poll released yesterday suggests the Tories would lose all but three of their Scottish MPs to the SNP in a general election.
The government is desperate to avoid a general election before it has delivered Brexit, which could see it punished by Eurosceptic voters for failing to take the UK out of the EU on schedule.
However, with little prospect of the Prime Minister’s Brexit deal getting through a hung parliament, speculation continues to swirl about a snap vote.
Meanwhile, Tory backbenchers have delivered an ultimatum to Downing Street for Theresa May – who promised to stand down if her deal is passed by MPs – to set out a clear timetable for her departure under any circumstances.
Senior figures in the powerful backbench 1922 Committee want her to go by 30 June.
With a number of contenders positioning themselves for a leadership bid, Johnson is understood to have held meetings with at least three Scottish Conservative MPs, telling them that he would not ruin their chances of re-election.
“He promised me he could save my seat,” a source told Scotland on Sunday. “I said only Ruth Davidson could do that”.
Johnson has shot to the top of unofficial surveys of Conservative members on who should succeed May.
However, Conservative MPs decide which two candidates will be put to a vote of the party membership in what is likely to be a crowded field.
Another Tory MP predicted that Johnson would likely face one of either Gove, Foreign Secretary Jeremy Hunt, or former Brexit Secretary Dominic Raab.
But Davidson, the Scottish Secretary David Mundell, and a number of other senior Scottish Tories are hostile to the idea of Johnson getting in to Downing Street, believing it will boost support for the SNP and Scottish independence, and ruin the Tories’ chances of winning power at Holyrood.
At last year’s Conservative Party Conference in Birmingham, where Johnson delivered an attention-grabbing speech on Brexit to steal the spotlight from an embattled PM, Scottish Tory sources revealed the existence of a covert campaign to talk down the former foreign secretary’s leadership prospects.
One source claimed in February that the plot – dubbed “Operation Arse” – had been a “great success”, but as Johnson’s leadership prospects have revived, the key players are reported to have continued discussions about how to defeat him.
Meanwhile, Gove is understood to be the leading contender among Scottish Tories, who trust his Unionist credentials.
“I’d be astonished if Michael doesn’t run,” said a Scottish Conservative source, who praised Gove and said his backstory, attending a state school in Aberdeen after being adopted, made him an attractive candidate to the party and the public.
“With May, you get the sense that she feels her attachment to the Union very deeply. The difficult decisions she’s made on Brexit reflect that.
“Even with David Cameron, you got the sense that when he talked about the Union, he meant it.
“I don’t think you can say the same thing about all the leadership contenders.”
The source added: “You don’t have to explain the Union to Michael. He completely gets it. When I talk to him about it, he finishes my sentences for me.”