To the untrained eye, it must look like Ed Sheeran just popped up out of nowhere. But he's been releasing EPs and touring almost constantly since he was 16 (playing more than 200 shows per year, he reckons). "I didn't go to the Brits school," he notes slyly in one of his songs.
Total immersion has paid its dividends. Ed's fans are like putty in his hands. Hormonal teenage putty. They know all of the words to all of the songs. They diligently scold a posse of shiny-suited city boys for their incessant yee-yaw at the bar. At the end of the show, one girl appears to faint into Ed's arms*.
So what's he done to provoke this adulation? Well, he's got the voice of a ginger angel, and the way he creates and manipulate backing tracks on the fly, using just a guitar and a loop pedal, is mesmerising.
But if I had to place a bet, I'd say his greatest appeal is his lyrics. They're semi-autobiographical tales of young love - a boy who gets dumped when his girlfriend goes to university; the couple who fight over whether or not to rescue an injured bird from the roadside. Yes, the couplets are clunky at times, but fans clasp their hands to their breasts as they sing along.
Ed's more recent songs display a maturing lyrical ability. Small Bump, about a teenage pregnancy, has a stinging twist in its final verse. The cheeky You Need Me But I Don't Need You has a nice line in self-deprecation, with lines like: "They say I'm up and coming like I'm in a fucking elevator" and, bafflingly, "[I'm] a young singer-writer like Gabriella Cilmi".
Actually, he's more in the mould of Jose Gonzales, or a dementedly upbeat Damien Rice. He fits nicely into the burgeoning scene of emotionally earnest singer-songwriters that's already given us Ben Howard, Jamie Woon, Benjamin Francis Poshsocks and... erm, Olly Murs.
The only issue is how he differentiates himself from those artists. But, whatever happens commercially, he has a certain future as a live performer.
The most electrifying moment of the night comes, ironically, when he unplugs himself from the PA system, grabs a stool and walks into the middle of the audience for a three-song encore. It was so good, I did something I swore I'd never do: I filmed it on my phone...
As one besotted fan screamed last night: "Gingers have tunes!"
* It later transpired that the 'fainting girl' had a panic attack, triggered by the heat and sheer weight of the crowd. Apologies for any offence caused.