Time Out says
Skip the endless charades and family arguments by spending Christmas Day touring London in an open top bus. Pass Buckingham Palace, Tower Bridge and Regent Street, while seeing the capital in all its glitzy festive splendour, decked out in thousands of twinkling lights for Christmas. Departs every 30 minutes between 9:00am and 4:30pm. Meet at 123-151 Buckingham Palace Rd. Find out more and book here.