The Captive Heart is a 1946 British war drama, directed by Basil Dearden and starring Michael Redgrave. It was written by Angus MacPhail and Guy Morgan. It is about a Czechoslovak Army officer who is captured in the Fall of France and spends five years as a prisoner of war, during which time he forms a long-distance relationship with the widow of a British Army officer. The film was entered into the 1946 Cannes Film Festival.

The film is partly based on the true story of a Czechoslovak officer in the RAF Volunteer Reserve, Josef Bryks MBE, and his relationship with a British WAAF, Gertrude Dellar, who was the widow of an RAF pilot.

In 1940, Czechoslovak Army Captain Karel Hašek escapes from Dachau and reaches France during the German invasion. He assumes the identity of a dead British officer, Geoffrey Mitchell, and becomes a prisoner of war after the German victory. Hašek is initially suspected of being a spy by the British prisoners, because he can speak German and no one else from Mitchell's unit was captured. Some wish to lynch him. But Major Dalrymple, the senior British officer, hears Hašek out and believes him, especially after Gestapo agent Forster visits the camp. Forster ran Dachau during Hašek's stay, and eyes Hašek suspiciously. To avoid exposure, Hašek must maintain the fiction that Mitchell is still alive. He gets a letter from Mitchell's abandoned wife Celia, reminding her husband of their two children and hoping to rekindle their marriage. Since the Germans read all prisoner correspondence, Hašek decides he must respond as if he were Mitchell, now returning Celia's affection. They exchange many letters, and develop a relationship.

Forster visits the camp several times, and Hašek fears he may be unmasked. Forster compliments him on his nearly perfect German and seems to recognise him, but cannot quite place him. Later, after almost four years captivity, Forster tells Hašek he knows he is not Mitchell and that his photograph has been sent to Berlin for identification. Soon after, it is announced that some prisoners are to be repatriated, but when Hašek goes for his medical exam, he is turned away.

The other prisoners devise a plan to save him without his knowledge. Private Mathews is on the repatriation list and volunteers to let Hašek go in his place. Major Dalrymple, Hašek's friend Lieutenant Stephen Hardy, and Mathews (a burglar in civilian life) break into the Kommandant's office and replace "Mathews" with "Mitchell" on the list. The plan works, and Hašek is "returned" to Britain.

Celia goes to meet the repatriation group, but is baffled when her husband does not appear. Hašek explains his situation to the British authorities, and enrolls in the Free Czechoslovak Army. He also travels to Celia's residence and breaks the news of her husband's death and his impersonation. She is devastated, and Hašek leaves. After she recovers, however, she rereads his letters, realizing that she has fallen in love with the writer. When Hašek calls her on the telephone on V-E Day, she is eager to speak with him.

Many of the prisoners were played by serving soldiers.^{[citation needed]}

Locations included the ex-naval prisoner of war camp Marlag, near Westertimke, which had remained largely intact after the end of the war the previous year, and Aston Rowant railway station.^{[citation needed]}