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The Double Clue is the seventh episode of series 3 of the ITV British television drama series Agatha Christie's Poirot featuring David Suchet as Hercule Poirot, first broadcast on 10 February 1991 in the UK. The episode is an adaptation of the Agatha Christie short story of the same name and was directed by Andrew Piddington with dramatisation by Anthony Horowitz.


Following a string of robberies, Poirot helps Chief Inspector Japp try to find the jewel thief. At the fourth scene of crime, the Detective finds no less than two promising clues: a glove and a cigarette case engraved with initials.

The TV adaptation is faithful to main premise of the original short story in the manner of robbery, range of suspects and how Poirot perceives the truth. However, in the original story Poirot reaches a conclusion very quickly. The adaptation draws out the story more and the plot develops differently. Hastings, Miss Lemon and Japp investigate the case on their own while Poirot takes a separate path, spending more time with Countess Rossakoff. The denouement and ending is different.

Comparison with Original Story[]

(may contain spoilers - click on expand to read)

Unlike the original story where Marcus Hardman insisted on discretion, the police are involved all the way. There has been a string of jewel robberies, three in three weeks. Japp tells Poirot that his job is on the line if he put an end to this crime wave. Marcus Hardman's is the fourth.

At Hardman's place, Poirot is introduced to Countess Vera Rossakoff. He appears smitten by her and over the next few days, spends time with her, visiting gardens and art galleries.

Hastings and Miss Lemon sympathise with Japp. They decide to follow up on the double clue of the glove and the cigarette case. They interview Mr Johnstone, Lady Runcorn and Bernard Parker.

Poirot has been smitten but not quite blinded. He hints to the Countess that he knows what is going on. He tells her that the police look at the case with eyes that are "too English". They see the Lords and Ladies and do not ask the basic question: which person was present at all the robberies. Perhaps, he tells the Countess, the thief was not English enough.

Hastings and Miss Lemon find Poirot learning the Russian alphabet. They tell him of their findings. The initials B.P. on the cigarette case points to Bernard Parker but Poirot reminds them that Lady Runcorn's maiden name is Beatrice Palmeston.

Like in the original story, Poirot gets the stolen necklace back from the Countess and then lets her go. But in the adaptation, he also has to lay a false trail for her. A policeman had reported seeing a tramp near Marcus Hardman's house the night of the robbery. Poirot tells Hastings to go back there the next day to follow up on this.

Meanwhile Poirot calls on the private detective firm of Redfern and Blake and asks for their help.

Hastings and Miss Lemon do as Poirot suggested and spot the tramp near Marcus Hardman's house. The tramp shoots at Hastings with a pistol and then drives off in an MG sports car.

Poirot gathers Japp, Hastings, Miss Lemon and the Countess at Marcus Hardman's house and sums up. Hasting and Miss Lemon's findings eliminate Johnstone because he is so wealthy and Lady Runcorn because she had come back to the house to meet Bernard Parker to sell some jewels secretly. That leaves the Countess.

The Countess tells the others that during the night she came back to the house to get her coat and also to take refuge from "that Japanese contralto" singing in the garden. While she was in the house, she saw and disturbed a figure.

Poirot says that was the tramp who could apparently afford an MG. He climbed into the house up the ivy and through the window. Hastings bumped into this tramp days later. Why did the tramp come back? Because he had dropped the jewel in his flight. Japp examines the ivy and finds the necklace.

As for the cigarette case, Poirot explains that it is Lady Runcorn's but she would never admit it because she had come into the house to meet Bernard Parker to sell it.

Poirot bids farewell to the Countess at a train station. He has arranged for her to be escorted by Redfern and Blake to make sure that she leaves the country. It was Redfern who was acting the tramp in the MG. It was necessary to lead Hastings off the scent. Poirot tells her she would continue her work and he must continue with his, but not in the same place. He returns her cigarette case. He tells her he knows that in the Russian alphabet, a B. is a V. and a P. is an R.

All is settled satisfactorily. But not quite. Hastings tells Miss Lemon there is a slight inconsistency he has noticed. The Countess mentioned a Japanese contralto. Surely if she had been in the garden, she would have known that it was the pianist who was Japanese.


Tropes and themes[]

Filming Locations[]

  • Myddelton Square and Inglebert Street - at the beginning, Poirot and Hastings are in a car. They come down the west side of Myddelton Square heading north. Then the scene is of a traffic light. After this, the scene switches to Hastings braking the car along Inglebert Street. They see a bridal family photo being taken at the door of St Marks Church Clerkenwell straight ahead of them. When the lights turn green, Hastings turns right onto the west side of Myddelton Square, going back the way he came!
  • Shrubs Wood, Chalfont St. Giles - Marcus Hardman's house
  • The Adelphi Building - Hastings and Miss Lemon interview Mr Johnstone
  • Englefield House, Englefield, Reading - Poirot's outing with the Countess
  • Scotland Yard, Victoria Embankment, London
  • Florin Court, Charterhouse Square, London (as Whitehaven Mansions)
  • Senate House, University of London - interior used as art gallery
  • Savoy Place, London - Poirot and the Countess walk down a colonnaded walkway then emerge on Savoy Place where he hails a cab for her. The colonnades possibly belong to the 80 Strand complex.
  • Paragon Train Station, Anlaby Road, Hull, East Yorkshire
  • Royal Hotel, 170 Ferensway, Hull, entrance to Paragon Train Station concourse - Poirot and Countess exit this doorway and then walk to train at end of show.

Research notes[]


Promotional Videos[]

See Also[]


Englefield House