Christopher Gray enjoys a sensational performance by Lyn Paul in Blood Brothers at the New Theatre

Audiences in Oxford this week are privileged to be offered, in Blood Brothers, a show that is destined to survive as long as the musical form shall live, reminding future generations of the way things were in Britain, specifically Liverpool, at the back-end of the 20th century.

Here is entertainment with purpose and power that has good reason to be considered as a work of art. That it’s also moving, and hugely entertaining, is an added bonus for the punters.

The show’s creator, Willy Russell, astonishingly supplied, single-handedly, the book, lyrics and music, hesitating long over delivery of the last, suspecting that others could do it better.

In this, he was probably right. The pounding monotony of the score, building towards an incantatory climax in Tell Me It’s Not True, rather leaves us hankering for rhythmic variety.

Nonetheless, one can only marvel at the skill with which Russell’s musical numbers propel the action forward, principally comic to begin with yet moving to a sombre, shattering conclusion.

In principal role of Mrs Johnstone, the former New Seeker Lyn Paul supplies a masterclass in technique, with a performance of huge emotional heft that never once goes over the top. She brilliantly conveys the heartbreak of an abandoned house-cleaner wife, saddled with a full Roman Catholic houseful of kids, who, facing the financially difficult prospect of two more – a pair of male twins – agrees to part with one to her prosperous but barren employer, Mrs Lyons (Paula Tappenden).

The chosen baby Eddie (Joel Benedict) enjoys a pampered and privileged existence, while Mickey (Sean Jones) endures all the privations of a working class home whose contents have a habit of being seized by their suppliers. ‘Easy terms’ they are not.

The lads inevitably meet, as seven year olds, resulting in some brilliantly comic scenes, as the two actors – both fully grown men – show us the movements and mannerisms of boyhood, while revealing the huge class gulf between the pair. This is beautifully illustrated when they mount their imaginary steeds, Mickey leaping on his with the full vigour of a cowboy, slapping the flanks of his mount, while Eddie canters off, bridle held high, like a competitor in a dressage event.

The pact of undying friendship sealed between them in an exchange of blood thus takes on a portentous significance. Watch and thrill.