Ed Sheeran is living proof that the pop industry is far more complicated than The X Factor would have you believe. You can just imagine Simon Cowell's reaction to this pasty-faced urchin, with his unfashionable red hair, tech-nerd hoodies and tendency to break into faux-Rasta beatboxing.
Sheeran should, in theory, have never got past open mic night at the student centre. He is scruffy and gawky, while his songs deal in the sort of lowest denominator sentimentality that have turned Coldplay into a laughing stock.
Somehow, though, he has become a superstar. He filled in for Roger Waters during the surreal faux Pink Floyd reunion at the London Olympics, shifted two million copies of debut album, +, and is one of the few artists capable of filling the O2 for three consecutive evenings.
In interviews, Sheeran has seemed rather baffled at his success. Seeing him in concert his incredulity feels perfectly reasonable. Slouching on stage, he exudes imperceptible levels of star power. For most of the night it's simply Sheeran, a guitar and some FX pedals, which he uses to loop vocals and grooves. The result is a performance that fizzles intermittently but never truly catches fire.
Granted, he has a strong voice and is clearly a decent musician. However, Sheeran's songs are very specifically about life as a confused, adrift Gen Y-er and if you're not attuned to his particular combination of hope and despair, finding a connection can be difficult. About to turn 22, he is at the age when relatively mundane events – a row with a girlfriend, a chance encounter with a homeless person – can appear hugely portentous and this probably explains his propensity to over-emote.
It certainly explains a fan-base that, based on tonight, is 90pc screaming teenage girls. It's Bieber fever for Leaving Certs, which presents difficulties as Sheeran tries to quieten the room for an indulgent folk tune early on.
The biggest problem is his tremendous lack of presence. Without a backing band and hobbled by a pretty paltry light show, the O2 stage dwarfs the Sussex native and at moments the scale of the surroundings threatens to overwhelm him.
That this never quite happens is testament to the quality of tracks such as 'Lego House' and his breakout hit 'The A-Team', wheeled out to boyband-worthy screams during the encore.
He's a gifted songwriter but gives the impression of being tremendously conflicted about his career's rocket-fuelled trajectory.
Sooner or later, you fear his ambivalence will catch up with him.