Tens of thousands of mourners in central London will watch as the Queen's coffin is taken from Buckingham Palace to Parliament on Wednesday with the solemn procession led by the King and his sons William and Harry along with other senior royals.
The Queen's body will then lie in state in Westminster Hall until her funeral next Monday, September 19.
Her final journey began on Sunday from Balmoral, where she died, to Edinburgh and then her body remained for one final night at Buckingham Palace after she was taken to London on Tuesday.