BORIS Johnson is to launch a Scottish “charm offensive” with a visit to and speech in Scotland to reinforce the Union if, as is widely expected, he becomes Britain’s new prime minister tomorrow.

But even before he takes over in No 10 a raft of UK ministers, opposed to a no-deal Brexit, including Chancellor Philip Hammond and David Gauke, the Justice Secretary, are preparing to resign their posts and avoid being sacked in a final act of defiance just before the new premier takes office.

Senior Conservative sources say the former London Mayor will prioritise two issues: securing a Brexit deal with Brussels and strengthening the Union.

To this end, he is expected to make a keynote speech on EU withdrawal later this week in the Leave heartland of north east England with another address on strengthening the bonds between Scotland, England, Wales and Northern Ireland during a visit north of the border over the weekend or next week.

READ MORE: Theresa May's legacy? She has enabled a right-wing populist takeover

Meeting Nicola Sturgeon will depend on her availability but supporters of Mr Johnson told The Herald he was keen to “avoid the imagery” of meeting the First Minister on the steps of Bute House. “He does not want to come across as a colonial consul-general surrounded by a mass of saltires,” noted one MP.

Another backbencher said: “The charm offensive will begin pretty quickly. He will be coming to Scotland within days and the expectation is he will make a keynote speech as part of his wider aim to strengthen the Union. He needs to send a positive message to Scotland early on; he is very well aware of that.”

One loyal Johnsonite stressed: “We must reunite the country under a banner of positivity….No one who has spent five minutes with Boris Johnson can deny they feel upbeat and emboldened.

“A Scottish “I can do” attitude trumps the grievance politics of the SNP…It’s time for Boris ‘do or die’. Holyrood and Westminster needs back bone and confidence,” he declared.

READ MORE: Donald Trump's biographer - 'I've seen it for myself in Scotland, the president is not what you would expect'

Mr Johnson’s Union strengthening strategy is due to include:

*setting up a Union Unit in No 10;

*beefing up the Scotland Office with one or more junior ministers in the Commons;

*supporting more direct funding of projects in Scotland, thereby bypassing the Scottish Government – expected to be one of the recommendations of the Dunlop Review;

*adding the words “Minister for the Union” to his prime ministerial title and

*retaining the Barnett Formula used to distribute additional Government spending, which he once derided.

While Ms Sturgeon has claimed a Johnson premiership would mean support for Scottish independence would “sky-rocket,” a Nationalist colleague suggested the Tory frontrunner could implement a Scottish strategy of populist measures to blunt the SNP’s attack. “He might not turn out to be quite so catastrophic as some people think. But let’s wait and see,” he said.

READ MORE: Glasgow is miles worse, and this time the SNP can't blame the Tories 

Tomorrow at 1130 at the QEII Centre across from the Commons, the Conservative changing of the guard will take place. It will follow Theresa May’s last Cabinet.

While Jeremy Hunt will make the short walk from Downing St to the conference centre, few expect him to cause an upset.

The next day after Scottish Questions in the Commons, Mrs May will take her last PMQs. She is expected to make her final speech behind a lectern in Downing St later that afternoon before going to see the Queen to formally resign.

By 5pm, her successor will be making his own speech in Downing St before starting the process of appointing his ministers; Cabinet ones first and middle-ranking and junior ones later.

Over the weekend, Mr Johnson is believed with aides to have been drawing up names for who will be in his new team.

Several ministers, who have made clear they could not sign up to Mr Johnson’s “no-deal loyalty pledge,” will resign before the new PM has the chance to sack them.

Mr Hammond took the dramatic step of pre-announcing his resignation on the BBC’s Andrew Marr Show.

Asked if he thought he would be sacked, the Chancellor replied: "No. I'm sure I'm not going to be sacked because I'm going to resign before we get to that point.

"Assuming Boris Johnson becomes the next Prime Minister, I understand his conditions for serving in his government would include accepting a no-deal exit on the 31st October and it's not something that I could ever sign up to.

"It's very important the Prime Minister is able to have a chancellor who is closely aligned with him in terms of policy and I, therefore, intend to resign to Theresa May before she goes to the Palace to tender her own resignation on Wednesday."

Mr Hammond’s move came after Mr Gauke - a former Remainer – announced he would do likewise.

"If the test of loyalty to stay in the Cabinet is a commitment to support no-deal on October 31 - which, to be fair to him, Boris has consistently said - then that's not something I'm prepared to sign up to,” declared the Hertfordshire MP.

Another who is expected to jump before he is pushed is Sir Alan Duncan. The Foreign Office Minister accused Mr Johnson of pushing Sir Kim Darroch, the former UK ambassador to Washington, “under a bus” for failing to back him publicly in the wake of the leaked diplomatic cables that so infuriated Donald Trump. A source close to Air Alan said he would “probably” resign on Wednesday too.

However, it is thought unlikely the raft of disgruntled ministers will include David Mundell, despite his railing against the prospect of a no-deal Brexit, saying it would pose the “biggest threat” to the Union and cause an economic catastrophe for Britain.

A source close to the Scottish Secretary stressed talk of jobs was “very premature and speculative” given the new PM was not yet in post. It is thought Mr Johnson will keep Mr Mundell in the Scottish portfolio, given his long experience, to help “mentor” any new ministers appointed to the Scotland Office.

But one Scottish Labour MP was clear Mr Mundell would put his career before his principles. “Those who are resigning are not going to get jobs anyway. They are unlike the Scottish Secretary, who is quite happy to serve Boris. Mundell has never been very principled. How many times has he threatened to resign; four or five?”

One question-mark hanging over a Johnson premiership is how the new PM will get on with Ruth Davidson; the two famously clashed over Brexit during the 2016 campaign when the Scottish Tory leader was on the losing Remain side.

One Scottish supporter of Mr Johnson said the rift between the two senior Conservatives was overplayed.

“They are okay together. Ruth’s been winning in Scotland, so everything will be fine. She needs him to be the best prime minister he can be and he needs her to get the better of Nicola Sturgeon. They have known each other for a long time and there is a mutual respect,” said the MP.

“They are going to rub along together just fine. They complement each other and they each need to make their relationship a success,” he added.

However, a Scottish colleague noted drily: “Who will give Boris the warmer welcome; Ruth or Nicola?”