FILE - Britain's Queen Elizabeth II and Prime Minister Boris Johnson, left, greet guests at a reception for the Global Investment Summit in Windsor Castle, Windsor, England, Tuesday, Oct. 19, 2021. In seven decades on the throne, Queen Elizabeth II saw 15 British prime ministers come and go, from Winston Churchill to Margaret Thatcher to Boris Johnson to Liz Truss. (AP Photo/Alastair Grant, Pool, File)