NIKI Evans follows in the footsteps of Clodagh Rodgers and Stephanie Lawrence in 1996, Bernie Nolan in 1999, West End understudy Sharon Byatt in 2005 and Marti Webb in 2008 in playing Mrs Johnstone in Blood Brothers in York.

Your reviewer has seen each one, and Evans, above all others, will stick in the mind, for being the most real. What makes her performance all the remarkable is that the Birmingham mother of two had never seen a theatre show, except for pantomimes, nor heard of Blood Brothers or impresario Bill Kenwright when she was offered the role on the West End stage after making the semi-finals of The X Factor in 2007.

Before anyone says “here’s another pop reality-show wannabe fast-tracked to top billing”, Kenwright and his producers know a talent when they see one, and Niki Evans is a natural for musical theatre with her powerful, emotional voice, her broad, expressive face – and in this instance a Scouse accent as thick as black treacle. She grew up on a council estate too, has lived a life before her big break, and it all shows in her terrific, deeply moving performance.

Willy Russell’s 1983 tragicomic musical must feel like an old piece of furniture at the Grand Opera House, so often does Andy Walmsley’s run-down Liverpool street design drop into place there, but no matter how often you see it, the cautionary tale of the twins separated at birth has you choking back the tears.

Evans’s performance – full of pathos, pain and love as well as buckets of ruddy humour – goes a long way to releasing the waterworks with her renditions of Easy Terms, Marilyn Monroe and Tell Me It’s Not True. Sean Jones (back in York from the 2008 production) and Paul Davies are no less impressive as Mickey and Eddie, the twin brothers cursed by the fateful superstition that if either should discover the other’s existence, they will die instantly.

Burdened with too many children and not enough money, and left by her husband, Mrs Johnstone sells one twin baby to the cold-hearted Mrs Lyons (Tracy Spencer), the rich, barren businessman’s wife up the posh hill for whom she cleans. Scally Mickey and scholarly charmer Eddie are pitched into a life either side of the class divide but their paths keep crossing, answering to the call of fate as it over-rides social circumstance.

From innocent child’s play, through teenage love pangs for Linda (Kelly-Anne Gower), to contrasting adulthood (pill dependency for Mickey, councillor status for Eddie), their worlds are watched over by the Faustian debt collector in the shadows, the Narrator (Craig Price, the only underwhelming performance in Bob Tomson’s excellent cast).

Guns are a constant motif in this doomed drama, an image that has become more and more potent over the years in Russell’s damning, unsentimental musical, where his heart-rending songs and social truths, his humour and humanity, now hit home harder than ever.

Blood Brothers, Grand Opera House, York, until Saturday. Box office: 0844 871 3024 or grandoperahouseyork.org.uk