John Siddaway

John Siddaway is a non-canonical character created for the 1993 film adaptation of The Case of the Missing Will in Series 5 of ITV's Agatha Christie's Poirot. He is the solicitor of Andrew Marsh.

Ten years before the events in the show, in 1926, Siddaway persuaded Andrew Marsh to make a will. This he did, leaving bequests to various people in his circle of friends. In 1936, over a lunch, Andrew Marsh mentioned to these same friend that he intended to change his will, although he did not hint at what changes he intended. Andrew Marsh was due to meet Siddaway the next day to draw up the new will, but he died during the night. Earlier on, however, Andrew Marsh ad verbally told his friend Poirot the in his new will he intended to leave his entire estate to his ward Violet Marsh and that he wanted Poirot to be his executor.

Although it was unusual to hold a reading of the will before the funeral, Siddaway did so anyway, hoping to dispel Hercule Poirot's belief that Marsh's death was not natural. However this plan backfired as Siddaway discovered, as he opened Marsh's docket, that the 1926 will gone missing. This only increased the mystery of Marsh's death.

John Siddaway is portrayed by Terrence Hardiman. Siddaway is married to Sarah and they have a son Robert Siddaway who, at the time of the events in the show, was doing his second year at Cambridge. He was also the boyfriend of Violet Marsh.