Here we go again. Reality TV — in this case the ITV talent show Grease is The Word, by and large the loser in the Saturday night ratings war with BBC1’s search for Joseph, Any Dream Will Do — plucks fledgeling performers from obscurity and deposits them on the West End stage.

The lucky pair, Susan McFadden (sister of Westlife’s Brian) and Danny Bayne, were selected to play Sandy and Danny from thousands of hopefuls by an audience vote and a panel made up of the seasoned producer behind this stage show, David Ian, the choreographer Brian Friedman, Liza Minnelli’s ex-husband, the professional weirdo David Gest and, er, Sinitta, probably best known for her execrable 1980s Stock Aitken and Waterman singles output, of which the dire So Macho was a lowlight.

Like Connie Fisher, the Sound of Music star, McFadden and Bayne are unknowns, but they are drama-school trained. It is to be hoped that they turn out to have the stamina for a West End run; squeals and whoops of delight at first glimpse of the duo on the opening night suggest that audiences are clamouring to catch them in action.

Bayne and McFadden make their initial entrance on plinths either side of Terry Parsons’s neon-lit set, looking rather like two shop-window mannequins. It’s an accurate indication of what’s to come; though they sing nicely enough, they go on to give rather stiff performances. McFadden — small, pretty and somewhat simpering — seems unsure what to do with her hands; Bayne — beefy but bland — manages a certain cheeky charm once he warms up a bit, but there’s no real chemistry between them. What’s worse, they both signally lack sincerity and sex appeal.

To be fair, what surrounds them is not a great deal better: they are supported by a cast, in David Gilmore’s efficient but lacklustre production, of garishly coloured and totally flat cartoon characters.

Here they come, the Pink Ladies and the T-Birds, stalking out of a cloud of dry ice, some of them looking conspicuously too old, rather than too cool, for school. There’s Jayde Westaby’s belting, bitchy Rizzo, Alana Phillips as the bubble-head Frenchy, and torpedo-breasted bottle-blonde Marty (Charlie Cameron). Danny’s boys, meanwhile, include Sean Mulligan’s eye-catching but vocally limited Kenickie, Bennett Andrews as a rather too creepily lascivious Sonny and Richard Hardwick as the chubby joker Roger who has a penchant for baring his buttocks.

They all flounce and pose their way through Arlene Phillips’s uninspired and, on the whole, undemanding choreography. Despite a burst of camp athleticism to Greased Lightnin, when a souped-up Caddy turns up amid some half-hearted pyroctechnics, and some vigorous hand-jiving at the hop, it is disappointingly short on dazzle. At no point do we care one iota what becomes of any of them or their teen romances.

The perennial popularity of Randal Kleiser’s 1978 film, the familiarity of Jim Jacobs and Warren Casey’s catchy score and the hoopla surrounding the ITV series have already proved enough to guarantee healthy advance ticket sales. And those who come expecting nothing more than a routine trot through well-loved material and a chance to see the two young competition winners in the flesh probably won’t be disappointed. It’s depressing that anyone should expect so little, but if reality TV is chewing gum for the eyes, for some this Grease will be bubble-gum fun — even if it is overstretched and losing its flavour.

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