As the Conservative leadership contest draws to a close, a Buckingham Palace spokesman confirmed on Wednesday that either Liz Truss or Rishi Sunak will be meeting the Queen in Scotland, rather than in London as is tradition.
The Queen will receive Mr Johnson on Tuesday September 6 at her Highlands home, where he will formally tender his resignation.
This will be followed by an audience with the new Tory leader, where she or he will be invited to form a government.
The news will inevitably heighten concerns about the health of the 96-year-old monarch.
Mr Johnson said arrangements for the handover will be tailored to make sure they suit the Queen.
He sidestepped a question about when he last spoke to her and if he was concerned that she would not be coming to London for the handover.
“I don’t talk about my conversations with the Queen, no prime minister ever does,” Mr Johnson told reporters during a visit to Barrow-in-Furness.
“But I can tell you we will certainly make sure that the arrangements for the handover will fit totally around her and whatever she wants.”
It comes as Ms Truss and Mr Sunak prepare to make a final push to win over Conservative Party members as the leadership hustings conclude on Wednesday.
The pair will aim to woo members during a final hustings in London before voting closes at 5pm on Friday, with Foreign Secretary Ms Truss widely tipped to emerge victorious when the winner is announced on Monday.
She and Mr Sunak are expected to once again lock horns over tax cuts and their competing visions for the UK economy, including on their plans to help households with the cost-of-living crisis.
Regulator Ofgem has confirmed an 80% rise in the energy price cap, which will mean the average household’s yearly bill will go from £1,971 to £3,549 from October.
Former chancellor Mr Sunak, who has acknowledged he is the underdog, has insisted he still believes he can cause an upset as he launched his latest criticism of his rival’s plans.
In an interview with the Financial Times, he said “a bunch of people I’ve spoken to say they still haven’t voted”, while he also highlighted the risks faced by Mr Johnson’s successor in Downing Street.
He said: “We have more inflation-linked debt by a margin than any other G7 economy — basically more than double. Because of the structure of QE (quantitative easing), we’re also particularly much more sensitive to an upward rate cycle than we have been.”
He added: “My general view in life – you can’t take anything for granted.”
The FT reported that Mr Sunak said it would be “complacent and irresponsible” for a prime minister and chancellor “not to be thinking about the risks to the public finances”, in a warning that the risk that markets could lose confidence in the British economy cannot be ignored.
In a rallying call ahead of the hustings, Mr Sunak also said in a statement: “Britain is the best country in the world to grow up in, start a family and build a business, and our future looks bright.
“But we can only get there if we tackle the challenges we face in the short term head on with honesty and a credible plan. I have the right plan, rooted in Conservative values, and I have been consistent, clear and honest throughout this contest that we must fix inflation first.
“Only by supporting people through this winter and gripping inflation can we lay the foundations for growth and prosperity – for lower taxes, a better NHS and a healthy economy making full use of our Brexit freedoms. That’s my vision for Britain, and I’ll work night and day to deliver it for the party and country I love.”
The Truss campaign has kept a lower profile in the final days of the contest, which included the decision to cancel a face-to-face TV interview with BBC journalist Nick Robinson.
A source from Ms Truss’s campaign said she changed her mind about the interview as she was focusing on winning as many votes as possible and preparing for government.