A familiar British ritual now features 2 new participants

For the lifetime of most people in Britain, the pattern has stayed the same. The old PM would meet Queen Elizabeth II at Buckingham Palace, followed almost immediately by the new one. In 2016, according to a briefing by parliament's library, Theresa May's car passed through the palace gates 32 seconds after David Cameron's had left. New PMs typically arrive in their own car and leave in an official one.
In between, the queen would ask them to form a government. In more recent years, there has also been a gesture to mark departing PMs' transition from public life to private: Their partners and children were invited to meet the queen. By the time Liz Truss succeeded Boris Johnson in September, the queen was too frail to leave Balmoral Castle in Scotland. So the politicians had to come to her.
Now, the rites have returned to London, and the monarch is King Charles III. And the new PM is Rishi Sunak. In one way, he is encountering this ritual unusually quickly: Elizabeth was queen for more than three years before bidding farewell to Churchill and welcoming Anthony Eden.