THE children’s novel Coram Boy, by the Indian-born British writer Jamila Gavin, was adapted a decade ago for the National Theatre in an acclaimed stage version by Helen Edmundson. The play won an Olivier Award before transferring to Broadway; the book, published in 2000, had earned Gavin a Whitbread Children’s Book Award.

This moving tale, fusing three intertwined stories, pays tribute to the Foundling Hospital, opened in 1741 by a philanthropic mariner, Thomas Coram. A protest against various ills of its day, it was designed for the “education and maintenance of exposed and deserted young children” and to alleviate the appalling condition of children’s health, while also providing a safe upbringing for abandoned or destitute infants.

Now, the play has received a vividly imaginative and touching fresh production at the very doors of Gloucester Cathedral, which, in part, inspired the story. Gavin has lived many years in the county, and set her tale of depression, family tensions, and redemption initially in Gloucestershire, and then in London. Gloucester’s amateur production, directed with originality and finesse by Jenny Wicks and Louise Partridge, proved a visual and musical delight: a costume drama that was vigorous and polished throughout.

Exposed as a callous villain, Otis Gardiner (Eliott Sheppard, in an artful performance) defrauds desperate young mothers of their money, promising to find their babies a home — before mercilessly disposing of the infants. Thomas Terry as his browbeaten young simpleton son, Meshak — a silent but powerfully affecting role — proved the most athletic member of the cast, hurtling to and fro, as Meshak bravely defies his father, secretly abducting and saving the life of the infant crucial to the story (whose parents were in the cast), the Coram Boy.

Fraser Martin as this growing lad, Aaron, was one of a troupe of half a dozen boy actors who lent vitality to this production. He was, poignantly, the gentle waif with the heart of gold. His (breaking) singing voice was enchanting. This third section, set in 1750 when Aaron is ten or 11, provided the redemptive denouement. This child’s restoration to his family, presented as a kind of miracle, was not the only point at which the production recalled a medieval mystery play.

Earlier scenes, immensely entertaining, were more problematic, occasionally puzzling dramatically, alternating as they did between different aspects of the central story. But the thoughtful and detailed direction and the cast’s zest rendered this outdoor staging an overwhelming success.

The shrewd Mrs Lynch (Shirley Halse) sympathises with the worries of the Coram Boy’s grandmother Mrs Milcote (Lynnette Kay)

The semi-circular layout, like an intimate amphitheatre facing out from the cathedral’s south door (designers: Laura Phillips and Tommima Lloyd-Winder), involved two sets of neatly wrapped scaffolding, one housing a vibrant 13-strong adult chorus, the other a trio of flute, violin, and keyboard. The fresh score composed by Lucas Bailey — elegantly alternating between Handel and echoes of the modern musical (Oliver came to mind) — was another notable success. The props, including a period handcart and a blue-sheet water scene, in which characters rose gaspingly from the waves, were splendidly devised; the costumes were colourful and TV-quality.

But it was the actors — spirited, alive, diligent, perfectly drilled — who gave this show its flair and energy. The first part, which focuses on an aspiring boy musician whose unforgiving knightly father bans him from his inheritance, was glitteringly presented. Paul Avery excelled as the explosive, domineering dad, an enjoyable brute who is finally happily reconciled; and Julia May was engaging as his wife, beautifully sympathetic. Shirley Halse as the family aide-de-camp, the one dispenser of common sense, brought huge intelligence to her role. Lynnette Kay as the grandmother of the boy was sweetly touching.

A cluster of girls sang, participated, or acted with verve, their speaking voices just occasionally a little muted. Harriet Willard (Alice) brought a nice cheeky spirit; but the most important girl character was Melissa (Merce Leigh), played as an entrancing grown-up by Mary Dunsby, whose affair with Alexander Ashbrook, the bullied and expelled son, produces the baby “Coram Boy” on whom Part Two centres.

This was a team effort of a high quality. Alongside Fraser Martin’s Aaron (Sir William’s unrecognised Foundling grandson) were the three other boys whose acting ability and singing talent were astounding.

Bertie Bird, who sang the knight’s son, young Alex, exuded sensitivity as well as marked personality; so versatility was one of his most impressive talents. He brought profound emotion to his prominent and taxing role.

His childhood playmate, Thomas Ledbury (Elliott Cowling), whose elder version — Eddie Saunders — brought nobility and refined poise, had qualities to match: a lovely singing voice, oodles of character, and an impish way of playing an audience.

Possibly the show’s real star was Finley Gould, as the Narrator, a very prominent Master of Ceremonies. His diction was masterly and his pacing was electrifying. With unbelievable professionalism, he galvanised the whole performance.

Thanks to the thought behind this production, the excellent discipline and marshalling of this substantial cast, everything went like clockwork. When everyone decamped into the nave (where the show began) to be bowled over by the “Hallelujah Chorus” — first heard in London at the Coram Hospital in 1749 — the conclusion was stunning. A brilliant idea, and it was treat that it was so stupendously well performed.