In the short story The Witness for the Prosecution, Sir Charles is leading the defence of Leonard Vole in the trial of him for the murder of Emily French.
Sir Charles only makes a brief appearance, at the trial. After Romaine gives her statement, he remarks that he has nothing to help Vole. His only theory was that Miss French's nephew was the culprit. However after letters revealing Romaine’s cheating is discovered Sir Charles exposes her as a liar saving Leonard Vole.
The character was later reworked into the character Sir Wilfrid Robarts, for Christie's own stage adaptation.