The queen, who is 96, has not been hospitalized and remains at Balmoral Castle, her estate in the Scottish Highlands, Buckingham Palace said in a statement.
Liz Truss takes over as prime minister at a time of deepening economic crisis. Her first cabinet appointments reward loyalists who supported her bid for office.
Taking power during the worst economic crisis since the Thatcher era, she will need all her ideological dexterity — some call it opportunism — to succeed.