For the first time ever, the Queen is to remain in Scotland to appoint a new prime minister. There are several options for making the 400-mile trip from Westminster.
Here, the PA news agency considers the potential routes for Boris Johnson and his successor to meet the Queen next week.
Travelling by private car would involve nine hours and 21 minutes on the road, according to Google Maps.
But stops to refuel/recharge and rest mean the actual journey time would be much longer.
The fuel cost for a typical petrol car would be around £100.
There are four direct daytime trains running from London King’s Cross to Aberdeen – 50 miles to the east of Balmoral – on Monday, the day before the politicians meet the 96-year-old monarch.
The quickest is the 10am departure, which takes seven hours and six minutes.
Tickets are available from £93.50 in standard class and £291 in first class.
But getting from Aberdeen to Balmoral would involve a taxi costing around £100, or they could take a local bus on route 201 for £11.50.
– Sleeper train
The 9.15pm Caledonian Sleeper departure from London Euston on Monday arrives in Aberdeen at 7.40am the following morning.
But anyone booking now is unlikely to get a good night’s sleep as all compartments with beds are sold out.
Tickets for a reclining seat cost £75.
– Commercial flight
A seat on a British Airways flight from Heathrow to Aberdeen – the nearest airport to Balmoral – on Tuesday morning costs £307 in economy and £603 in business class.
The flight takes one hour and 35 minutes.
A video was posted online showing the Duchess of Cambridge disembarking a commercial aircraft at Aberdeen Airport with her children Princess Charlotte and Prince Louis en route to Balmoral earlier this month.
In the highly unlikely event Mr Johnson and his successor want to travel by coach, they could buy a ticket on the Megabus service which departs London Victoria at 8am on Monday for £48.29 each.
After a change of coach in Glasgow, they would arrive in Aberdeen at 10.25pm.
– Private flight
A private plane or helicopter is a likely option for the politicians.
The journey would take around 45 minutes by a private jet or two-and-a-half hours by helicopter.
Both options would cost thousands of pounds for private passengers.
Clean transport campaign group Transport & Environment said private jets emit up to two tonnes of CO2 in just one hour, around a quarter of the amount emitted by an average person in Europe for an entire year.
A spokesman for the group said: “Flying on a private jet is probably the worst thing that the new PM can do for the environment and on his/her first day.
“Jets are five to 14 times more polluting than commercial planes per passenger, and 50 times more polluting than trains.
“Both transport options are possible for the new PM for the travel up to Balmoral.
“In the middle of a cost-of-living crisis, some form of energy sobriety would be a sign of respect for the British people.”
Alethea Warrington, campaigns manager at climate charity Possible, said: “Having just experienced a summer so hot that runways melted, the UK urgently needs leadership on the climate crisis.
“The new prime minister’s travel choice for the journey to Balmoral will provide an early opportunity to show whether or not they will be stepping up to this challenge.
“They can do this by choosing climate friendly transport such as train travel, rather than taking an unnecessary flight or even travelling by an incredibly polluting private jet.”