Annie Mole's, webmaster of Going Underground, daily web log (blog).
If you like this you'll LURVE One Stop Short of Barking, THE fun and informative BOOK about travelling on the London Underground.
I don't think he was even playing anything Xmassy, but was certainly bouncing around his spot with great gusto and with a number of people stopping to watch.
Look out for more Santa Tube spots particularly when hundreds of them invade London on December 15th for the annual Santacon UK.
"The magic, mystery & sometimes maddening shortcomings of London's Tube are documented with love, enthusiasm & sometimes despair by its unofficial social historian." The Guardian