Alternative credibility may be assured through the backing of Pitchfork and the involvement of producer Alex Metric, but make no mistake - Charli XCX - real name Charlotte Aitchison - is unashamedly 80's pop.
Taking to a stage decked out in red roses and backed by two men stood behind keyboards, the 20-year-old singer is all dark eyeliner, fluffy hair, big platform shoes and a deeper-than-average voice. Her songs are full-on electro anthems with huge choruses, which at their best could be described as Marina backed by Depeche Mode; at their worst Marina backed by Ladyhawke's backing band.
Fortunately the heights are far more numerous, especially the big New Order drum beats of 'Lock You Up', which boasts a thrilling finale aimed directly at the dancefloor. She also brings a similar template to her cover of Echo & The Bunnymen's brooding 'Killing Moon', turning it into something that could have been lifted from an alternative Top Gun soundtrack.
The meteoric rise of headliner Ed Sheeran in the last year, is a pretty astonishing achievement for a young man and his acoustic guitar. His two million-selling debut '+' may, however, reflect a growing desire among youngsters (the lion's share which tonight's enthusiastic crowd members undoubtedly are) to seek out an alternative to Simon Cowell-approved form of pop star.
Rarely seen out of his winning jeans and t-shirt combination, Sheeran certainly provides that alternative. With his messy ginger hair and Suffolk twang, he represents something far more down to earth and realistic - if no more challenging - than a winning X-Factor contestant. Indeed, Sheeran knows both his appeal and his audience all too well - forever eager to involve the audience by dividing them into sections for what he calls "my gospel choir", Sheeran implores everyone to sing like no one is listening: "Come on! This isn't X-Factor!"
Sheeran's infectious enthusiasm and enjoyment from performing is endearing, and it becomes very easy to warm to him between songs. But while Sheeran does so well in filling a stage simply with his own presence and a loop pedal, he seems to take his songs far more seriously than he takes himself. This is a shame, because his earnest songs are often littered with sixth form poetry and platitudes, only occasionally providing something with a little more depth. It would be great to be able to capture the likeable, self-deprecating and insightful Sheeran chatting with fans onstage in more of his songs.
His voice, too, is often unassuming and lacks expression live, perhaps explaining why his cover of Nina Simone falls so flat. But when the 21-year-old launches into more upbeat rap songs, such as his cover of Lil' Kim's 'Lighters Up', Sheeran shows a lot more promise and character. His passionate 20 minute rendition of the single 'You Need Me, I don't Need You', during which he is joined by Devlin, Sway, Chip and Wretch 32, is another case in point. It provides both the finale and highlight to a set that drags on far past the 90-minute run time Sheeran promised at the start of the evening.
The low point occurs when Sheeran introduces yet another cover version as "one of the top 20 songs ever written", after which everyone in the audience is surely surprised to see Gary Lightbody walk onstage to help sing Snow Patrol's 'Chasing Cars' - a weepy, wet flannel of a song that leaves a sensation in the mouth somewhere between a vomit and a yawn.
Perhaps Sheeran enjoys being onstage too much, building up songs steadily on his loop station but too often getting carried away with an upteenth chorus. Try as he may - and despite his huge success and popularity - with only one album up his sleeve, Sheeran does not yet have the material to sustain a two-hour set.
Below: photos from Ed Sheeran's iTunes Festival show, 2012