In a historic first for her 70-year reign, Queen Elizabeth II will greet the UK’s new prime minister at Balmoral rather than Buckingham Palace.

The 96-year-old monarch won’t be travelling the 1,000 miles round journey from Scotland, according to a representative for Buckingham Palace; instead, on September 6, the departing leader Boris Johnson will fly from London to the north, followed by an audience with his successor.

A palace insider said the decision was made to hold the audiences at Balmoral in order to give the Prime Minister’s calendar some kind of assurance, CNN reported.

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According to the source, if the queen experienced episodic mobility issues the following week and the trip to London or Windsor had been planned, it would have required last-minute changes to the original plans.

After months of scandals that rocked his government and resulted in hundreds of cabinet resignations, Johnson was forced to resign as the head of the Conservative Party in early July. After making his declaration, a large field of candidates for the leadership position was narrowed down to two: Foreign Secretary Liz Truss and former Chancellor Rishi Sunak.

The two have spent the summer becoming friends with the party’s 160,000 rank-and-file members. On Monday, the outcome of that vote will be made public.

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The winner will receive an invitation from the Queen to form the next government and become her 15th prime minister as the head of the largest party in Parliament.

One of the Queen’s primary ceremonial duties as Head of State is to appoint a new prime minister, along with the State Opening of Parliament and the signing of parliamentary legislation into law. At the great set-piece event in May, Princes Charles and William commanded the stage, with the heir to the throne reading the government’s legislative programme for the coming year on behalf of his mother.

It had been 59 years since the Queen had last missed the occasion. Invoking patient confidentiality, the palace highlighted the monarch’s “episodic mobility problems” but declined to provide more information. 

These ongoing problems, which she has been dealing with since a brief hospitalisation in October of last year, have also interfered with other events, such as her Platinum Jubilee festivities in June.

During the Queen’s seven decades on the throne, the ceremony next week will mark the first time a prime minister has formally offered their resignation or been installed outside of Buckingham Palace.

One of the most recent examples of how events over the past year have been altered for the Queen’s “comfort” was her arrival to Balmoral Castle earlier this month. The ceremony is usually marked by an honour guard at the 50,000-acre estate’s gates, but this year’s troop inspection took place in private.