It's a shame to see the negative reviews, after years of incoherant nonsense finally we have a superb christmas special. The underlying premise is clever and well executed.
Jenkins shows she may have a successful secondary career as an actress (and given this is her first acting role that was particularly impressive) and Gambon is superb as ever.
I can understand some people taking issue with things such as the shark sleigh ride, it definitely only works at christmas (the Christmas themes run non stop throughout the episode). Buy it, but perhaps don't watch it until next christmas. It's not bad who, but it is fantastic holiday cheer (and I feel sorry for anyone who was bah humbuging it all the way through).