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Vanessa Redgrave as Mary in the 1974 film

Mary Hermione Debenham[1] is one of the main characters in Murder on the Orient Express.

Mary has been played by various actresses, including Vanessa Redgrave, Natasha Wightman, Jessica Chastain, and Daisy Ridley.

Daisy Ridley as Mary in the 2017 film


Mary Debenham was 26 years old at the time of the events of the story.

Mary was the personal secretary to Sonia Armstrong, the mother of Daisy Armstrong. She was also the professional governess to Sonia's younger sister Helena Goldenberg. She was holding this post at the time Daisy Armstrong was kidnapped.

The perpetrator of the crime, Cassetti was arrested and tried but got off on a technicality because of his wealth and influence. Linda Arden, the mother of Sonia Armstrong, gathered a group of interested parties for the purpose of avenging the crime and bringing the criminal to justice. Mary joined this group. Fellow group member Hector MacQueen succeeded in obtaining a position as secretary to Cassetti, then using the alias of Samuel Edward Ratchett, a dealer in antiquities who traveled frequently to the Middle-east. MacQueen, who was in control of his employer's schedule, was able to pick a suitable journey for them on the Orient Express. Other members of the group then travelled to Istanbul to join the same train.

At this time, Mary was a governess to two young children in Baghdad and about 26 years old.[2] She travelled from Baghdad to Istanbul on the Taurus Express with Colonel Arbuthnot, a friend of Colonel Armstrong, with whom she had developed a romance. On the way to Istanbul, she and Arbuthnot alighted at Konya during a brief stopover. Hercule Poirot was also on the Taurus Express. At Konya, Poirot overhead Arbuthnot address her by her first name, as well as Mary saying to Arbuthnot, "Not now. Not now. When it's all over. When it's behind us. Then..." This was to play a significant part in Poirot's deductions as to what happened in the death of Cassetti.

On board the Orient Express, Mary occupied berth No. 11, sharing a second-class compartment on the Calais coach with Greta Ohlsson who was in the lower berth, No. 10.


Murder on the Orient Express (1974)

In the 1974 film, Mary Debenham is played by Vanessa Redgrave. In this portrayal, she teaches shorthand in Baghdad, unlike in the novel, where she was a governess to two young children in Baghdad.

At the time of the kidnapping of Daisy Armstrong, Mary was secretary to Sonia Armstrong. She was seen arriving at the Armstrong house with Sonia and Colonel Armstrong and being surrounded by reporters. There is no mention in this adaptation that Mary was also the governess to Helena Goldenberg. Also, in this adaptation, the conversation between Mary and Arbuthnot, which Poirot overheard, took place on the ferry across the Bosphorus and not at Konya.

In the murder scene, Mary receives the dagger from Colonel Arbuthnot, and is the third person to stab Rtachett, saying that it is for Mrs Armstrong, who took her into her home. She then hands the dagger to Greta Ohlsson.

Murder on the Orient Express (2001)

In the 2001 TV film adaptation, Mary Debenham is played by Natasha Wightman. She works for a relief organisation which looked after the welfare of children in Baghdad and was travelling back to London on vacation. She claimed she was afraid of flying.

In this adaptation her alibi was that she was in a compartment with Foscarelli, Arbuthnot and MacQueen having "a party" according to the conductor Pierre Michel. They were having drinks and discussing politics.

Although Mary denied having been in America, she gave herself away by using words such as "vacation" instead of "holiday" and "attorney" instead of "solicitor". Elena von Strauss who later admitted to being Sonia Armstrong's sister told Poirot that Daisy Armstrong had a tutor, an old red-haired Scottish woman named Lassiter. Poirot deduced that it was Mary Debenham. Elena was trying to misdirect. She searched desparately for a name and settled on Lassiter. "Lassiter and Debenham" was a well-known American department store.

At the end of the movie, Poirot reveals in a voiceover that Mary Debenham and Bob Arbuthnot got married in a discreet ceremony in Seattle.

Agatha Christie's Murder on the Orient Express computer game (2006)

According to her passport, Mary was born on January 9, 1902. This makes her older here than in the book where she was described as being 26.

At the time of the events on the train she had just left a post as governess to two children at Baghdad and was on her way back to London hoping to find another job.

She lived in West Sussex, and her father was a clergyman.

Agatha Christie's Poirot: Murder on the Orient Express (2010)

In the 2010 adaptation of Murder on the Orient Express, Mary Debenham is played by Jessica Chastain. In this adaptation, she was a governess at the house of the A.O.C. (the Air Officer Commanding i.e. the senior Royal Air Force officer) in Baghdad just prior to the events on the train. Colonel Arbuthnot was a friend of the A.O.C. and had visited him in Baghdad. There, Arbuthnot met Mary and they fell in love with each other.

At the beginning of the movie, Poirot overheard a conversation between Mary and Colonel Arbuthnot, similar to the novel and other adaptations. In this adaptation, the conversation took place in the streets of Istanbul. Poirot later asked Mary about the meaning of this conversation, but she would only say that she was not at liberty to say.

Mary suffers from paralysis on the right side of her body. Poirot deduces that she was the Armstrong family's governess, and that the paralysis is due to an injury she suffered when Daisy Armstrong was kidnapped.

In the reconstruction of the murder during the denouement, Mary is the first to stab Ratchett, and does so with her left hand. She then hands the knife to Hector MacQueen.

Murder on the Orient Express (2017)

She grew up with a love of geography and was a teacher of geography. Mary temporarily lived with her sister, at 61 Bevenden Street, London, England.

Physical Description

In the novel, Mary is tall, slim, and dark. Her skin has a delicate pallor. She has a burnished black head, cool, impersonal grey eyes, and wavy hair. She has a cool, calm, collected personality.

In her introductory scene, Mary wears a dark-colored travelling dress made of thin material.

For her scenes on the train, Mary wears a grey French shirt, and a neat black suit.

She wears a pale mauve dressing gown for sleeping.

  • In the 2017 film, Mary has dark brown curly hair with red highlights, hazel eyes, and red lips.
    • Her main attire is a navy blue cardigan, an orange neck tie blouse, a knee-length plaid tweed skirt, and black t-strap Mary Jane shoes.
    • In other scenes, she wears a tweed plaid suit to match her skirt.


  • Mary is right-handed.
  • Even though her character's costume in the 2017 film is is tweed, Daisy Ridley herself is allergic to wool.
  • In the 2017 film, Mary lives with her sister until her next employment, at 61 Bevenden Street, London.
    • This is a real address: it is Finn House, an apartment complex in Hoxton, an East End district of London.


  1. According to Chapter 11 of Part 2 of the novel, Mary says her full name is Mary Hermione Debenham.
  2. Chapter 11 of Part 2 of the novel