The ABC Murders

The killer writes to Poirot before he starts, which is either very bold or very stupid. The letters are taunting, playful in a nasty way, and they lay the scheme out in advance: victims and crime scenes, chosen in alphabetical order. A railway guide beside each body is the closest the case has to a signature. Then the bodies start to appear, three of them in short order, and Chief Inspector Japp and Inspector Glen are baffled, and who could blame them.

The killer has made one mistake, and it is a personal one. He has challenged Hercule Poirot to unmask him, which turns a difficult police file into a matter of pride. The rest of the episode is Poirot deciding that the alphabet is the least interesting thing about the case. The order of the killings tells you less than the man hiding behind it, and a man who enjoys himself this much will not stay hidden for long. He lets the killer talk, and a man who writes letters will always talk.

Clive Exton and Agatha Christie wrote it, Andrew Grieve directed. David Suchet anchors the whole business, with Hugh Fraser as Hastings and Philip Jackson as Japp. Around them stand Donald Sumpter as Cust, Donald Douglas as Franklin Clarke, Nicholas Farrell as Donald Fraser, Pippa Guard as Megan Barnard, Cathryn Bradshaw as Mary Drower, Nina Marc as Thora Grey and David McAlister as Inspector Glen.

And it is a pleasure to watch Poirot take an enemy who desperately wants an audience and refuse to give him the show. Every letter is a boast, and every boast is a thread to pull on. The killer's need to be seen is almost as much a part of the crime as the murders themselves, and that is the weakness Poirot intends to use.