Due to mobility concerns, Queen Elizabeth broke with convention and appointed the new prime minister at her Scottish retreat, Balmoral Castle, rather than Buckingham Palace in London.

A spokesperson for Buckingham Palace announced Wednesday that the queen would see outgoing Prime Minister Boris Johnson and his unnamed successor on September 6 at her summer residence, Balmoral.

In July, Johnson was compelled to resign after dozens of ministers quit the cabinet protesting his scandal-plagued premiership.

Shortly after meeting with Johnson, the 96-year-old monarch will meet with either Foreign Secretary Liz Truss or former Finance Minister Rishi Sunak, according to a spokeswoman.

Polls indicate that Truss is the apparent frontrunner in the Conservative Party leadership election to replace Johnson, which will be revealed on September 5.

According to a royal insider, appointing the new leader at Balmoral will provide certainty for the future prime minister's schedule and prevent last-minute alterations if the queen encounters mobility challenges.

Queen Elizabeth, under whose reign there have been fourteen prime ministers, has had to limit her public appearances in recent months due to these difficulties. She also spent a night in the hospital in October for an unidentified ailment.

"We will certainly make sure that the arrangements for the handover will fit totally around her and whatever she wants," Johnson told Sky News.

As head of state, the British monarch traditionally chooses the new prime minister following an audience at Buckingham Palace, which is part of the day's spectacle, which includes television cameras and helicopters following official automobiles as they enter the palace grounds.

Since the reign of Queen Victoria, every British leader has been appointed at Buckingham Palace, the BBC reported, citing constitutional scholar Vernon Bogdanor.

In June, the queen and her family stepped onto the balcony of Buckingham Palace to wave to adoring spectators during a celebration commemorating her record-breaking seventieth year in the British monarchy.

Last month, at the Commonwealth Games in Birmingham, her son and heir to the throne, Prince Charles, spoke on her behalf.