British sources reported on Friday that Queen Elizabeth II will miss out on a traditional highlight of her summer trip to Scotland because of persistent mobility problems that have been lasting for nearly a year.

The Queen of Britain's walking and standing problems have been forcing her to cancel a series of public engagements. This has also prevented her from returning to London to appoint a new prime minister.

The queen had this weekend been expected to attend the Braemar Gathering near her remote Balmoral retreat in northeast Scotland.

Read  next: Queen Elizabeth II to miss Jubilee service amid ‘discomfort’

The event is the most well-known on the Highland Games circuit, and it is always held on the first Saturday in September. Since the mid-nineteenth century, senior royals, including the monarch, have attended the games on a regular basis to see feats of strength and endurance.

Events include tossing the caber, in which kilted competitors endeavor to lift and throw a full-length log of Scots Pine.

Attendees this year -- the first since 2019 because of the coronavirus pandemic -- include the queen's eldest son and heir, Prince Charles.

The queen, who came to the throne in 1952, traditionally appoints the country's prime minister at an audience at Buckingham Palace in London.

In a change to a convention, she will perform the constitutional role at Balmoral next week, instead of returning to the British capital.

Normally the handover of power is a swift affair, given the palace's location, just a short distance from parliament and government offices. But the 1,000-mile (1,600-kilometre) round-trip to the Scottish Highlands will lengthen the process, delaying key appointments to the new government.

Boris Johnson, who resigned as Conservative party leader in July, will formally tender his resignation as prime minister to the queen Tuesday. She will then ask the new Tory leader -- either Foreign Secretary Liz Truss or former finance minister Rishi Sunak -- to form a new government.

Truss and Sunak have been vying to succeed Johnson. The winner of the vote of Tory MPs and grassroots party members closes on Friday, with the winner due to be announced on Monday.