This is one of the best short stories I have read in a while. It has all the horror and humour of a Charles Stross Laundry series story (have a go if you haven't read one of these), which it is. A Christmas story with Lovecraft overtones and a nice antidote to more sugary Christmas stories. Events take place with the hero Bob Howard on duty in a British Government supernatural organisation over Christmas; with a creepy take on the nature of Father Christmas.
Good, tongue-in-cheek fun, that is well written, at a good price.