A police officer stands guard outisde the entrance to King Edward VII hospital in west London on December 20, 2019, on the afternoon Britain's Prince Philip, Duke of Edinburgh was admitted. - Prince Philip, the 98-year-old husband of Queen Elizabeth II, went into hospital on Friday, December 20, 2019 for precautionary treatment on a pre-existing condition, Buckingham Palace said. (Photo by Tolga AKMEN / AFP)