For years I wondered whether the ingenious premise of Agatha Christie’s “The Witness for the Prosecution” influenced John le Carré to use the same premise in The Spy Who Came in from the Cold. So I asked him, and he replied. But first the facts.

“Witness,” written in 1924, is a short story of just twenty-six pages. Leonard Vole is on trial for murdering an elderly woman whose will makes him the principal beneficiary. The woman’s maid reports, and ultimately testifies, that she heard a man speaking with her employer at 9:30 PM on the night of the murder. Leonard tells his solicitor that he returned home that night at 9:20 PM, and that his wife can verify the time, providing him with an alibi.

Questioned by Leonard’s solicitor, the “wife,” Romaine Heilger (called Christine in Billy Wilder’s film version, starring Marlene Dietrich), states that she is an Austrian actress and that they are not married. She astonishes the solicitor by saying that Leonard returned home at 10:20 PM the night of the murder with blood on his coat and confessed his guilt.

On the eve of the trial, the solicitor receives a letter telling him to come to a rented room where someone has evidence that Romaine’s account is false. Accepting the invitation, he meets a mysterious woman who hands him a letter in Romaine’s handwriting. The letter, addressed to “Max,” her “Beloved,” says that she will have her revenge on Leonard by testifying that he came home that night with blood on him and confessed to the crime. “I shall hang him, Max.”

At trial Romaine repeats her damning accusation and steadfastly repeats it on cross-examination. Leonard’s barrister then produces her letter, which totally discredits her testimony. She breaks down on the stand, confesses to her lies, and confirms Leonard’s alibi.

With the accusation of the principal witness undermined, the jury quickly comes to the conclusion that Vole is innocent and acquits him. Afterward Leonard’s solicitor sees Romaine and realizes that, in disguise, she was the woman who handed him the fake letter. She explains her ploy: “I know something of the psychology of crowds. Let my evidence be wrung from me, as an admission, damning me in the eyes of the law, and a reaction in favor of the prisoner would immediately set in.”

The solicitor, appreciating the ploy, says he sees that Romaine knew Vole was innocent. “You do not see at all,” she replies. “I knew—he was guilty!”

The story originally ended at that point, but, responding to protests that a guilty man should not get away with the crime, Agatha Christie added a new ending. Vole abandons Romaine, who promptly retaliates by killing him right in the courtroom. The play and the film end the same way.

The premise that undermining an accusation will induce a court to believe that an accused person is innocent is not grounded in logic. Although an accuser is lying, for whatever motive, the defendant may nonetheless be guilty. But the jury in “Witness” jumped to the conclusion that the defendant was innocent, exactly as Romaine had hoped.

Thirty-nine years later in Spy, Alec Leamas, the spy who had hoped to come in from the cold, is dispatched to East Germany, believing that his final mission is to destroy Hans-Dieter Mundt, chief of East German counterespionage, by making what Leamas believes is the false accusation that Mundt is a double agent working for British intelligence. Unbeknownst to Leamas, Mundt really is a double agent.

Leamas’s mission is orchestrated by le Carré’s famous spymaster, George Smiley, who initially takes several steps to provide credibility for Leamas’s accusation. First, Smiley creates the impression that Leamas left his job with British intelligence under a cloud, suspected of financial irregularities. “In the full view of his colleagues he was transformed from a man honourably put aside to a resentful, drunken wreck.” A job is arranged for him at a library where, as Smiley anticipated, he meets and becomes romantically involved with Liz Gold, the secretary of a Communist cell in London. Leamas commits a minor assault intended to land him in jail. Upon his release, he is approached by an East German agent who begins the process Smiley anticipated of recruiting Leamas to become a defector. Ultimately Leamas appears as a witness before an East German secret tribunal, where Mundt has been put on trial on the accusation of Mundt’s deputy, who has become suspicious that Mundt is a double agent.

Unbeknownst to Leamas, Smiley has carefully created grounds for showing that Leamas is lying when he testifies against Mundt and has made sure that German intelligence becomes aware of these grounds. The key basis for discrediting Leamas is bringing Liz Gold (called Nan Perry in the film version) before the tribunal. She testifies that after his release from prison Leamas told her there was something he had to do, someone he had to get even with, and when it was over, he would come back. She also testifies that a man named Smiley came to her apartment after Leamas left and assured her that “friends” would pay her rent, all of which confirmed that Leamas remained in the employ of British intelligence and was falsely accusing Mundt.


His accusation undermined, Leamas realizes that Smiley had planned the whole thing to save his double agent and tries to save Liz by admitting to the tribunal, “It was an operation, a planned operation.”

After learning that British intelligence has orchestrated Leamas’s accusation that Mundt is a double agent, the tribunal comes to the opposite conclusion—Mundt is a loyal East German officer. Mundt then arranges for Leamas to go over the Wall back to West Berlin and pretends to do the same for Liz Gold. But she is shot and killed climbing the wall, and Leamas, disillusioned, chooses not to come in from the cold, climbs down, and is also shot and killed.

The structures of the two stories are not identical. In “Witness” the plot to mislead the tribunal by undermining an accusation of guilt is conceived by the witness herself. In Spy the plot is conceived by the witness’s superior, with the witness unwittingly used as a pawn. In “Witness” the witness knows her accusation is true but wants a jury to believe she is lying. In Spy the witness, who also believes his accusation is true, wants a tribunal to believe him. But the premise of the two plots is the same: showing that an accuser is lying will induce a belief that the opposite of the accusation is true.

Three years ago I wrote to le Carré and asked “whether you had Agatha Christie’s premise in mind when you wrote The Spy Who Came in from the Cold, if not, whether you thereafter became aware of the use of the premise in the earlier work, and in any event, whether you are aware of the use of this premise in other works of fiction.”

I added, “Having presided over many criminal trials in eight years as a trial judge and read many trial transcripts in thirty-two years as an appellate judge, I have seen many accusations attacked but never by use of a preplanned basis to discredit the accusation with the result that the jury believes the opposite of the accusation.”

The reply from le Carré included the following:

Your question has been put to me before, and I have tried to answer it honestly. I did indeed see the Agatha Christie play, but I have no idea whether it was before or after I wrote The Spy Who Came in from the Cold, nor whether the device of entering a witness in order to discredit him could have been in my head when I came to write the novel. But I am sure that the notion did not consciously present itself to me during the short and turbulent time of writing. I think there are a whole bunch of influences that kick around in one’s head at such a time, and one draws on them because they are apposite, often without recognizing where they come from. Maybe that happened in this case, though I am inclined to doubt it. I had, for a short time in my life, been close to all manner of deceptions, and the process of inside-out thinking was very familiar to me!

I thank you again for writing.

Yours sincerely,
John le Carré