The X Factor TV show has its critics. The critics seem to focus mainly on three arguments: the ‘soap opera’ style of the judges criticisms, the possible faking of audience vote numbers, and the extensive use of cover versions. Cover versions get a bad rap. Finalists are accused of copying and not bringing anything original to the plate. There’s an art to the cover though, and it has its advantages. A song already known and loved by millions, a template already set out, a template that can be altered by the creative singer, a song that can be ‘made your own’ without having to bore an audience with an acoustic original you wrote during hard times… That’s what the packed seated Odyssey patrons are here to see and hear this evening.

Like the TV show, the tension is racked up to high heaven. At exactly 8pm there’s a countdown provided by ‘the voice of X Factor’ Peter Dickson, causing a flurry of excitement as teens – screaming all the while – rush to their seats. Celebrity Big Brother winner Rylan Clark breaks the tension with the introduction to Take That’s Back For Good, a gentle nudge at judge Gary Barlow and a high octane mashup of Gangnam Style, Groove Is In The Heart and Pump Up The Jam. And high octane really is the order of the evening, with act after act being wheeled out to the tune of pop classics old and new, controversial press-maligned Chris Maloney gleefully singing I’m Still Standing whilst posing with a cane, Union J storming through Taylor Swift’s Love Story and When Love Takes Over winning the battle of the boy bands against also-rans District3 whose ability to turn somersaults while surrounded by sportswear-clad street dancers doesn’t quite cut it.

After every act is introduced with their most memorable song, the meat of the concert arrives, each of the seven acts getting a chance to spend their time on stage as if it was truly their show. At times farcical with District3 taking photos of the audience and lifting each other in attempted Marx Brothers fashion to the pensive, Ella Henderson taking to the piano for a version of Cher’s Believe, asking the audience to sing along and becoming visibly emotional when they comply. And it’s an emotional evening. X Factor denigrators aside, from the point of view of these performers they have had a life-changing experience, one that would never have happened without the TV talent show and their gratitude is palpable, especially that of gospel choir graduate Jahmene Douglas. A shy, shivering wreck at the start of the TV auditions, helped only by his ability to hit spectacular Jackie Wilson-esque notes, he’s a different person now. Never one for Rylan-style showcasing, he’s still a much more capable performer than he was, shrugging his velvet jacket, owning the big voice and taking the audience through a jazz-tinged set with At Last a classy moment in the evening’s pure pop explosion.

Winner James Arthur is saved until last. Moving from ‘with guitar’ to ‘without guitar’ [X Factor’s definition of a true musician] he protests that he’s losing his voice and we’ll have to help him but although he does sound a little hoarse his prowling animalism is still there, the denim-clad lad from the wrong side of the tracks not seeming out of place when surrounded by writhing Bond girls in red while singing Feeling Good, a version with more in common with Muse’s Matt Bellamy’s falsetto than Nina Simone. Finishing with his recent number 1 song Impossible the words seem wrenched from the pit of his stomach, his ability to seem genuine, undiminished by the attention.

There’s the obligatory group number to finish, U2?s Beautiful Day filling the stadium as the lyrics are split between the seven acts, acts who laugh and carry each other around with the disbelief that this is actually happening. It’s a feel-good gig, one that will probably not change the lives of anyone in the audience but the participants are making the most of their already changed lives, full of so much joy it should be bottleable.