Trivia / Ghost Stories for Christmas

• What Could Have Been:
  • Lawrence Gordon Clark wished to adapt Count Magnus for the original series, but couldn't get the budget.
  • Mark Gatiss had planned a "very grim" original ghost story, set in a hospital, for the 2021 episode, but decided it wouldn't be appropriate given the current pandemic, and opted to adapt M. R. James' The Mezzotint instead.