Some reviewers from Styles of Dying critique the episode for its "clichéd denouement" and the logistical improbability of the heist's timing (requiring the theft to occur in just a few seconds). Plot & Mystery Breakdown
For a deep dive into how the episode was expanded for TV, the Poirot Project review details several major changes:
A formal analysis titled "Poirot Investigates The Jewel Robbery At The Grand Metropolitan" examines Poirot's use of logical reasoning and interview techniques. It explores how his methodology remains relevant to real-world investigations while acknowledging the "supernatural" level of deduction often present in fiction.
In the original story, Mr. Opalsen is an oil mogul; the TV version changes him to a theater producer to add suspects and drama.
"Poirot" Jewel Robbery at the Grand Metropolitan (TV ... - IMDb
Analysts note that the recurring "Lucky Len" gag was added specifically for the show to give Poirot a reason to finally take the case out of annoyance.
The TV adaptation replaces the original "valet" accomplice with Saunders , the Opalsens' chauffeur.
Several helpful resources and academic analyses are available for " Jewel Robbery at the Grand Metropolitan " (Series 5, Episode 8), ranging from plot breakdowns to critical comparisons of Agatha Christie’s original short story versus the television adaptation.