For the fifth time in twenty-five years, Robert Hardy once again plays Prime Minister Sir Winston Churchill. Needless to say, Sir Winston is not a character in the original novel.
At the end of the program there is a dedication to the memory of Michael Attwell who played "Archie Stone" in this episode. Sadly he passed away a month before this episode aired.
The original 1931 novel has Emily Trefusis as the chief investigator and does not feature Miss Marple at all.
This film is based on the first Agatha Christie novel to incorporate the supernatural or occult as part of the plot-line.
Timothy Dalton (Clive Trevelyan) previously played Agatha Christie's first husband Colonel Archibald Christie in Agatha (1979).