The musical gestation of this opera was protracted, and was reflected in a number of musical projects in Vaughan Williams' life. For example, the familiar hymn 'Who would true valor see' is sung by the chorus in Act II, Scene I, from a tune written in 1906. Vaughan Williams' earlier one-act opera The Shepherds of the Delectable Mountains, from 1921, was incorporated into Act IV, Scene 2 of the later opera. His Symphony No. 5 also made use of themes originally conceived for his John Bunyan project.. He wrote a 1940 motet on Mr. Valiant-for-Truth's speech for mixed chorus. The BBC commissioned Vaughan Williams for incidental music for a 1942 radio dramatization of The Pilgrim's Progress. Herbert Murrill has characterized the opera as "summarizing in three hours virtually the whole creative output of a great composer".
The Covent Garden performances were not a success, and the company dropped the opera from its repetoire in 1952. However, a student production at the University of Cambridge in 1954 met with greater approval from the composer, notably for the performance of John Noble as Pilgrim.
The opera contains 41 individual singing roles.
Prologue: Bunyan in Prison The opera opens to the chords of the psalm tune 'York'. John Bunyan is in Bedford Gaol, completing his book The Pilgrim's Progress. He stands, faces the audience, and begins to read from the opening of the book. As he does so, a vision of Pilgrim appears, carrying his burden. A curtain falls to conceal Bunyan, and Pilgrim is alone on stage, reading and in a state of lamentation.
Evangelist directs Pilgrim towards the Wicket Gate. Four neighbors, Pliable, Obstinate, Mistrust and Timorous, appear to warn Pilgrim away from his journey. But Pilgrim dismisses them and continues.
Outside of the House Beautiful, Pilgrim "stumbles up to the Cross" and kneels before it. From off-stage, the voices of Three Shining Ones are heard. They then greet Pilgrim and relieve him of his burden. After Pilgrim knocks on the door of the House Beautiful, the Interpreter bids him welcome, as a chorus greets him. The Interpreter marks Pilgrim's forehead in blessing, and after receiving a white robe, Pilgrim enters the House.
Watchful, the house porter, prays for the safety of the house's denizens and for them to enjoy the blessings of sleep.
The Herald asks who will go forth on the King's highway. Pilgrim volunteers, and a scribe notes his name in a book. Pilgrim then receives "armour of proof", and begins his journey.
In the Valley of Humiliation, a chorus of Doleful Creatures, howling, surrounds Pilgrim as he enters. Apollyon enters and challenges Pilgrim in single combat, but Pilgrim prevails. The fight has exhausted Pilgrim, but two Heavenly Beings, Branch Bearer and Cup Bearer, restore Pilgrim with leaves from the Tree of Life and water from the Water of Life. Evangelist then returns and gives Pilgrim the Staff of Salvation, the Roll of the Word and the Key of Promise. He also warns Pilgrim to take care at town of Vanity.
At the fair in the town of Vanity, "all the pleasures of man" are for sale. Pilgrim enters, and averts his eyes from Vanity Fair as the crowd surrounds him and offers their wares, from Lord Lechery to Madam Bubble and Madam Wanton. The crowd asks what Pilgrim will buy, and he replies: "I buy the truth!" The crowd mocks Pilgrim, who denounces them as followers of Beelzebub. Lord Hate-good then appears, before whom the crowd brings Pilgrim. Witnesses, including Superstition, Envy, Pickthank and Malice, as well as Madam Bubble and Madam Wanton denounce Pilgrim. Lord Hate-good asks for the crowd's verdict, and they demand death. Lord Hate-good orders Pilgrim to be imprisoned.
Pilgrim laments that God has forsaken him. In his despair, clutches at his chest. He feels the Key of Promise, and after he has put it in the lock, he is instantly freed from prison and his bonds are gone. He resumes his journey.
The Woodcutter's Boy is chopping firewood at the edge of a forest when Pilgrim enters, asking how far there is to go to the Celestial City. The Boy replies "not far", and points out that one can see the Delectable Mountains on a clear day, The Boy then notices Mister and Madam By-Ends as they approach. Mister By-Ends points out that he has become a "gentleman of quality". He offers to keep the Pilgrim company on his journey, but Pilgrim replies that those who would travel with him must be willing to stand "against the wind and tide". Mister and Madam By-Ends refuse, preferring creature comforts and his "old principles" to poverty. They leave, and Pilgrim resumes his journey.
At the Delectable Mountains, three Shepherds are at evening prayer. Pilgrim approaches them and asks if he is on the path to the Celestial City. They reply yes, and after asking why he wishes to journey there, invite Pilgrim to rest with them momentarily. The voice of a bird sings praises to God. A Celestial Messenger appears and tells Pilgrim that "the Master" summons him that day. The Messenger ceremonially pierces Pilgrim's heart with an arrow "with the point sharpened with love". The Shepherds anoint Pilgrim. The Messenger directs Pilgrim on the path to the Celestial City, to which he must first cross the River of Death. The Shepherds pray for Pilgrim.
In darkness, a trumpet sounds in the distance. The scene brightens, and voices from Heaven welcome Pilgrim to the Celestial City, at the completion of his journey.
Epilogue Back in Bedford Gaol, again with the 'York' psalm tune present, Bunyan addresses the audience, holding out his book as an offering.