LONDON, UNITED KINGDOM - JULY 2015: (This image is free of charge for a month from release. Use or reproduction in any format on any platform after October 8, 2015, must be approved first by Royal Communications at Buckingham Palace.)  In this handout photo released by Buckingham Palace on September 8, 2015, Queen Elizabeth II is seated at her desk in her private audience room at Buckingham Palace with one of her official red boxes which she has received almost every day of her reign and contain important papers from government ministers in the United Kingdom and her Realms and from her representatives across the Commonwealth and beyond. The photo has been taken by Mary McCartney in July 2015, to mark the moment she becomes the longest reigning British Monarch. (Photo by Mary McCartney/Her Majesty Queen Elizabeth II via Getty Images)