LONGFORD [Jim Broadbent] is a thought-provoking story inspired by real events in the life of British Lord Frank Pakenham, the 7th Earl of Longford, and his controversial headline-making friendship with one of England's most notorious criminals. Longford, a devout Catholic, often visited prisoners because of his passionate belief in forgiveness and society's need for prisoner rehabilitation.
In 1965, he begins visiting Myra Hindley [Samantha Morton], a young woman serving a life sentence for murdering children with her lover Ian Brady [Andy Serkis]. Though Longford encountered public outrage, discouragement from his wife Elizabeth [Lindsay Duncan], doubt from his family, and criticism from his colleagues and the press, he continued to visit and exchange letters with Hindley. After learning that she once converted to Catholicism, Longford encourages her to return to the church and ask for God's forgiveness.
After the Prime Minister removes him from the House of Lords, he devotes his time to crusading for Hindley and other prisoners. His wife eventually joins the crusade after reading Hindley's letters, meeting her and seeing the horrible prison conditions. She suspects that Hindley is receiving harsher punishment because she is a woman. Longford takes Hindley's cause public, talking to the press about her case and defending her as an accomplice corrupted by Ian Brady.
At first, Hindley is grateful for Longford's efforts and seems to make progress in her return to the church. Later, she unexpectedly rejects his help and shocks him with the news that she lied to him about the murders. Once this information is made public, Longford's good name is damaged even further. Longford begins to question his religious beliefs, but reaches a deeper level in his Catholic faith when he is able to forgive Hindley for her transgressions against him.
Many years later, she asks him to visit her once again and he complies. He shares with her the importance of their friendship to him. Until the end of his life in 2001, Longford continues to visit prisoners, crusading for prison reform. Hindley dies in prison in 2002 after serving 36 years, even though the average life sentence is 12 years for men convicted of similar crimes. To this day, Ian Brady continues to serve his life sentence.