Willy Russell’s classic musical Blood Brothers finally closed at the Phoenix Theatre in 2012 after 24 years, but the show’s extraordinary sell-out success on tour proves there’s plenty of life still in it – and judging by the packed auditorium at the Orchard Theatre last night, that’s not about to change any time soon. A story that seamlessly slips from laugh-out-loud humour to devastating tragedy in the blink of an eye, Blood Brothers never fails to grip the audience firmly by the heartstrings and pull us, sobbing, to our feet for a protracted standing ovation.

Set in Liverpool, the show explores a nature versus nurture debate through the story of the Johnstone twins, Mickey and Eddie (Sean Jones and Mark Hutchinson). With one too many mouths to feed and a husband who’s run for the hills, their mother (Lyn Paul) agrees to give one of her unborn sons away to her wealthy employer (Sarah Jane Buckley), who can’t have children of her own. Raised in very different homes, the brothers grow up knowing nothing of each other, but fate intervenes to repeatedly bring them together, with dramatic consequences that ultimately prove tragic for everyone.

There’s not a huge amount I can say about Blood Brothers that I haven’t said before; this was my fourth visit and not much has changed in terms of the staging or design in Bob Tomson and Bill Kenwright’s production, which gives the show a comforting familiarity (also, why mess with a winning formula?). This even includes the cast; Blood Brothers is a show that seems to have an incredible power to retain cast members, and it’s a pleasure to see veterans Lyn Paul, often described as the definitive Mrs Johnstone, and Sean Jones, who’s rapidly becoming – for me at least – the definitive Mickey, reprising their roles. Both continue to display the necessary energy, both physical and emotional, to make their characters and their journey compelling, and are complemented by equally strong performances from Dean Chisnall as the Narrator, Mark Hutchinson as Mickey’s charming, well-spoken twin Eddie, and Alison Crawford as Linda, the girl who inadvertently comes between the brothers.

Perhaps one of the secrets of Blood Brothers‘ success is that it’s not your typical musical. With the exception of the well-known finale, Tell Me It’s Not True, in which a mother’s heartbreak routinely reduces most of the audience to a weeping mess, there aren’t really any dramatic “belt out the big solo” numbers, and instead each of the characters gets their own signature theme, which recurs throughout the show – most notably Shoes Upon the Table, the Narrator’s ominous warning, which returns no fewer than six times. As a result, the music feels like a much more natural part of the story, and the action can continue uninterrupted without pausing to make way for big showpieces.

The other unique thing about Blood Brothers is that it’s very funny, which is surprising considering our looming knowledge from the very beginning of the tragedy to come. The enjoyable sight of adults playing mischievous children and awkward teenagers guarantees a lot of laughs, and the whole script is shot through with a cheeky Scouse humour that constantly catches us unawares, so when things suddenly turn serious in Act 2, it’s all the more shocking.

The show might leave us a bit emotionally battered, but it’s worth it, and obviously I’m not alone in thinking this; Blood Brothers has a loyal following who willingly return to have our hearts broken again and again for the sheer pleasure of watching the story and its characters develop. This production doesn’t add anything new, but why mess with something that’s already perfect as it is?

Blood Brothers is at the Orchard Theatre until 26th November.