Peter Baker 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 son of Margaret Baker, Andrew Marsh's housekeeper and her husband Walter Baker, the local police sergeant.
After the death of Andrew Marsh and the mysterious disappearance of his will, Dr Martin Pritchard suggested to Poirot that Marsh might have a son who might be his rightful heir. He speculated that this son might be Peter Baker since Marsh and Mrs Baker were thought to be found of each other. However Margaret insisted that Andrew only admired her from afar. After coming back from Australia, Andrew had been sent to France during the First World War. Peter was conceived while Andrew was away and by the time he came home on leave, Peter was already three months old.
Peter Baker is portrayed by Neil Stuke. At the time of the events in the episode, Peter is a soldier in the British Army. He had come home on two weeks leave before departing for duty in Palestine.