London serves as both a practical destination in the investigation and the later setting for the criminal proceedings against John Cavendish. Poirot’s unexplained journey there coincides with John’s arrest; in September, the household’s circle regroups in the city as the case moves from suspicion to trial.

A Destination in the Investigation

After Hastings learns of the arrest, he hurries to find Poirot but discovers that the detective is not at home. An older Belgian tells him that Poirot is believed to have gone to London. The news leaves Hastings unsure whether Poirot anticipated the arrest or helped bring it about, and he returns to Styles uncertain how to handle the announcement there. His immediate concern is Mary Cavendish and the shock the news may cause her.

London’s role at this point is therefore partly defined by absence: Poirot is away from the village, and Hastings cannot ask him what the arrest means. The city marks a break in the investigation’s familiar local routine without yet revealing the purpose of the detective’s journey.

The Legal Case and Its Competing Accounts

The dispute that eventually reaches the courts is rooted in the household’s inheritance arrangements. At an inquest, Mr. Wells explains that Emily Inglethorp’s will from the previous August left her entire fortune to John, while Lawrence was already entitled to a considerable sum under his father’s will when his stepmother died. The arrangement was presented as fair because John would have to maintain Styles. Poirot points out that Emily’s remarriage automatically revoked that earlier will under English law, a rule Mr. Wells confirms.

A later paper complicates the inheritance story: servants say Emily summoned them and had them sign beneath her own signature, while blotting paper covered the text above it. At John’s trial, the prosecution depicts him as financially strained and argues that he poisoned Emily for gain, framing the family benefactor’s death and the destroyed new will as parts of a single plan. The defence counters that John knew the earlier will in his favour had been revoked by Emily’s remarriage and proposes to produce evidence identifying the person who destroyed the new will. In this way, the legal meaning of marriage and testamentary change becomes central to the rival accounts presented in London.

September in London

By September, the family party has taken a house in Kensington, with Poirot included in the group. Hastings has a job at the War Office and is able to see them frequently. The move places the household together in London while the prosecution of John advances, but it does not bring private certainty: Poirot remains troubled by the missing “last link,” and Hastings fears the consequences for Mary if John is not acquitted.

On September 15, John appears in the dock at the Old Bailey, charged with the wilful murder of Emily Agnes Inglethorp, and pleads not guilty. Sir Ernest Heavywether is engaged to defend him, while Mr. Philips opens the case for the Crown. The prosecution alleges premeditation, financial desperation, a quarrel with Emily, and a disguised purchase of strychnine intended to implicate Alfred Inglethorp. The defence contests that account, including the claim that John was the man who visited the chemist, and points to evidence against other possible suspects. London thus becomes the setting where the village’s scattered clues and family disputes are tested as courtroom claims.

The City and the Unfinished Proof

The narrative’s movement to London changes the scale and form of the case. At the village inquest, the medical finding establishes that Emily died from strychnine poisoning, with at least three-quarters of a grain, and probably about one grain or slightly more, recovered. In court, the same death is reframed through questions of motive, identity, and proof. The shift from the inquest at the Stylites Arms to the Old Bailey shows how a medical conclusion can be secure while responsibility remains contested.

London also holds together the personal and public stakes. Hastings’s War Office employment lets him remain close to the family, while John’s appearance in the dock makes the household’s crisis a formal criminal case. Yet the city does not itself settle the mystery: as the trial begins, Poirot still lacks the final link he needs. Its significance lies in bringing the characters together at the point where private suspicion must withstand public scrutiny.