Britain's Queen Elizabeth records her annual Christmas broadcast in the White Drawing Room in Windsor Castle, next to a photograph of the queen and the Duke of Edinburgh, in Windsor, Britain, December 23, 2021.

Victoria Jones/Pool via REUTERS/File Photo.

LONDON, Jan 23 (Reuters) - Britain's Queen Elizabeth flew by helicopter to her Sandringham estate in East England on Sunday after delaying her traditional Christmas trip for a month due to COVID-19, a Buckingham Palace source said.