It must have happened to many a headteacher: a visit from a pushy parent demanding that their child be admitted to a school. It certainly happened to the Master of Magdalen College School when Welsh singing teacher Clara Davies arrived in Oxford determined to overturn a decision not to admit her son Ivor. “My son can sing,” she announced. Mrs Davies won the day.

Ivor remained at MCS until his voice broke at the age of almost 17. Described as “a dead loss academically”, Ivor was then asked to leave.

So he first scratched out a living accompanying his mother’s pupils, but eventually found fame as Ivor Novello, composer of immensely popular musicals.

Now present-day MCS teacher Alex Thomas has written a musical celebrating Ivor’s life, and it was premiered at this year’s MCS Arts Festival.

The show starts in the school common room. “I say you fellows, can you think of a word that rhymes with Venus that isn’t terribly rude?” asks one of Ivor’s chorister colleagues.

Subsequent scenes show him enlisting as a pilot in the First World War (he promptly crashed his plane), and becoming a Hollywood swoon actor (“Gimme profile,” snarls director D. W. Griffith).

Along the way, co-star Gladys Cooper (Margaux Wilson) and singer Vivian Shaw (Jessie Leach) fall for him, and there’s a splendid, hissy-fit row with Noël Coward (Ollie Burrows).

This show is a major achievement. Thomas’s period-sounding score flows seamlessly into the three original Novello numbers also used. At the performance I saw, Thomas occasionally asked too much of the soloists, but the well-drilled company chorus numbers really took flight (director Tom Attenborough).

Professional actor Ned Stuart-Smith, brought in to play Ivor, blended perfectly with the otherwise wholly MCS cast. Only the ending seemed odd: a gay love song as Ivor finally declares his devotion to Bobbie Andrews (James Digby). A bit risky in the 1920s surely?