Theatrical spinoffs from popular movies are usually ill-conceived and redundant; a double whammy from which you’re less likely to come back than Chrissie Watkins after a swim off the beaches of Amity Island. But Ian Shaw, son of late actor and occasional hellraiser, Robert Shaw, has found a refreshing and exhilarating way to make a companion piece to Steven Spielberg’s Jaws that isn’t dead meat for the sharks, or whatever metaphor you care to use. I promise there won’t be any more of these.

If you know Spielberg’s film you’ll agree that for all its Hitchcockian brilliance, the crux of it – its heart as Ian Shaw tells us, ventriloquising his Dad, is three men trapped on a boat, killing time, exchanging stories and facing their fears – their Melville-like odyssey culminating in Quint’s Indianapolis speech; one of cinema’s most memorable (and chilling) monologues.

In a theatrical masterstroke, not to mention a shrewd piece of psychological storytelling, playwrights Shaw and Joseph Nixon use this backdrop and the same dynamic – the three men, Robert Shaw, Richard Dreyfuss and Roy Scheider, mirrors of their movie personas (a drunken working class curmudgeon, preppy insecure spoilt brat, and grounded everyman respectively) to explore their off screen relationship on the much delayed oceanic leg of the shoot. Robert Shaw’s diaries form the backbone of the script but there’s import from the present, namely Ian Shaw’s reflections on his father’s character and a sense of regret and loss that is implicitly cyclical – not least when Shaw senior laments his truncated relationship with the playwright’s grandfather.

These notes in the margin – the equivalent of annotating his father’s autobiography, might have been overdone, but Ian Shaw is content to use understatement when putting words in his emphatic father’s mouth. Shaw senior enjoys the fantasy that had he and his father had more time the son could have helped his Dad overcome his demons. He wonders aloud, would his gestatory sponsor be proud of him if he could see him now? Given the fidelity of Ian Shaw’s performance, Shaw senior surely would be.

If the play has a little too much conspicuous, and therefore clunky meta-commentary on the Jaws series and the future blockbusters their movie would kickstart in earnest, the reflections of the recreated cast on the artistic merit of the film they’re making have the feel of authentic exchanges. Robert Shaw, ever the artist, dismisses it as a “money making machine” – typical of the decade’s high concept empty spectacles. Liam Murray Scott’s Dreyfuss wonders if it will make his name. Demetri Gortisas’ Scheider laments his typecasting. We’re left to reflect that by today’s standards that crowd pleaser – which like the play it’s inspired has actors not stars, looks thoughtful and character driven. Steven Spielberg just rolled over a stone. He didn’t know it was plugging a hole in the universe.

The Shark is Broken but the play isn’t thanks to the plausible merging of actors’ identities with their now iconic characters. It’s a poignant and often very funny piece about art, commerce and men at a pivotal moment in their careers. But fundamentally it’s a son’s eulogy for his dead father. Few get to play their Dads on stage. Fewer still embody them so vividly. For fans of Jaws that’s reason enough to see this production. Those who do will be treated to a sometimes uncanny but always insightful and philosophical rumination on life; a fantasy based on a memory from a fantasy. Not to be missed.