Towards the end of Jersey Boys, Frankie Valli looks back on his career. “When everything dropped away and all there was was the music – that was the best,” he says. To some extent, the same could be said of the show. For all the wit and candour of the script, which tells the turbulent story of The Four Seasons with laudable honesty, it can be quite slow going. The performance really lifts off when the boys hit the big time and the show hits the songs: every number is a toe-tapping hit and delivered superbly in Des McAnuff’s production, with Ryan Molloy catching beautifully Valli’s soaring, arresting falsetto.

The musical (recipient of four Tony Awards and now in its third year on Broadway) makes its London debut here, splicing the group’s instantly memorable songs with their rags-to-riches, warts-and-all (and some of the warts are quite sizeable) story. We begin in the unlovely industrial belt of 1960s New Jersey, where the four Italian-American boys grew up. Music, as the band’s lead guitarist Tommy DeVito realised, was a route out and, alongside petty crime and spells in jail, he busily tried to get a band together. He spied in the teenage Valli a rare talent. But years of slog followed, with the band switching name and style, playing half-empty dives, doing bread-and-butter backing singing and getting murkily embroiled with the Mob.

The trouble is that while we need all this back-story to understand where the boys were coming from and the wilderness years before the big break, it makes for a fidgety first half hour. It is not easy to cut anything that is going to matter later, so everything goes in. However it is all touched on so briefly that the show rarely ducks beneath the surface. This doesn’t matter so much when the incident in question is a dismal gig in Nevada but when it is a fake murder and its impact on Valli, or, later in the show, his grief over the loss of his daughter, the drive-by style can be unsatisfying. And while the long lead up to the big break (it is 14 songs in) means that we share the group’s elation when they finally burst into “Sherry”, it means we also share their frustration beforehand.

Where the book, by Marshall Brickman and Rick Elice, really does shine is in its revealing use of personal detail. The show is peppered with golden nuggets: we learn that “Sherry” was such a last-minute piece of inspiration for songwriter Bob Gaudio that he had to get Valli to sing it down the phone to the producer; we see Gaudio trying to chat up girls by quoting TS Eliot; we discover that Nick Massi would meticulously iron his shirts twice and, astonishingly, got his children to think of him as an uncle to protect them from heartache.

And the show perceptively explains the appeal of the group (the back-story is admittedly instrumental here). Klara Zieglerova’s set combines a grim industrial backdrop with bubble-gum-coloured pop art projections. These boys knew their audience – the blue-collar workers and sad-eyed waitresses in diners. They knew the need for escape and the potency of the catchy song, and so we got “Big Girls Don’t Cry”, “Walk Like A Man”, “Rag Doll”, “Can’t Take My Eyes Off You” and “My Eyes Adored You”.

The songs are brilliantly delivered here but the performers also invest their characters with colour and shade. Glenn Carter is edgy as the bullish, impulsive DeVito, Philip Bulcock is troubled as the reticent Massi and Stephen Ashfield is touching as the quiet, determined Gaudio. And Ryan Molloy excels as Valli, soaring away from his personal heartbreak on that extraordinary, disquieting voice.

★★★☆☆

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