The Queen held an audience with Theresa May, who tendered her resignation as Prime Minister and First Lord of the Treasury. The Queen next received Boris Johnson and requested him to form a new Administration. He is the 14th Prime Minister of Her Majesty's reign.
The Queen should have started her Balmoral break last week but she was held back due to, you know, this whole situation. Buckingham Palace is already open to the public for the summer, so she briefly came in from Windsor Castle for the prime minister switcheroo and then left the palace immediately after.