(FILES) In this file photo taken on June 6, 2015, Britain's Prince Philip, Duke of Edinburgh arrives ahead of the racing on the second day of the Epsom Derby Festival in Surrey, southern England. - 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 Ben STANSALL / AFP)