Released as part of the BBC's 2009 "Doctor Who Adventure Calendar."
This episode takes place in 2013.
"A Ghost Story for Christmas" is also the title of a line of BBC dramas that ran annually from 1971 - 1978 and was revived in 2004-5, 2010 and 2013.
In spite of its title, the story makes no reference to Christmas or ghosts whatsoever.