It speaks volumes, then, that the final track of the pre-show mix - the one to which she ends up walking out - is Kate Bush’s “Running Up That Hill”. She quite literally could’ve chosen any other song, but that's what she went with. It’s one thing for writers to draw parallels between the two women, but another entirely for the prescribed pretender to the throne to actively, cheekily, invite the comparison. To use a sporting analogy, it’s a bit like NBA star LeBron James reverting to Michael Jordan’s number, 23, when he re-signed for the Cleveland Cavaliers. You knew he was daringly suggesting that you place him in the same bracket as the greatest of all time, and more than that, he knew that you knew - that was the point. Lorde does the same tonight.

She is not shy about measuring herself against the very best, nor should she be after June’s scintillating sophomore record, Melodrama, which confirmed that Pure Heroine was no fluke. She played a ton of festivals this past summer and found room for a headline date at Brixton Academy back when she was promoting her debut album, but for the most part, she kept the road at arm’s length back then. It’s easy to forget how young she was, and ironically, she doubtless made the thoroughly sensible call to avoid live over-exertion herself.

All that means that there’s a certain weight of expectation to this, her first full-blooded stab at the global touring roundabout, amplified by the fact that her fanbase incorporates a number of different factions; chin-stroking musos and screaming teen pop advocates are out in equal force, and she caters to both. The latter get the kind of stage set they’d expect - two costume changes, an array of neon props, and heartily encouraged singalongs - whilst the former aren’t denied the opportunity to pore over the musicality of it all.

This is hardly the most extravagant backdrop of all time, especially when you consider that it’ll make it to much bigger rooms than this old theatre, which holds a little shy of four thousand at a push. Stage right, there’s an old-fashioned telly - a CRT one that has a decidedly non-slender rear section. Comically, Lorde is barely old enough to remember this kind of set. Right before she takes the stage, it flashes through a violently random series of images, from an old pizza ad to Matt Damon proclaiming what a bloody good time he was having on The Graham Norton Show to footage of test missile launches, never more relevant than now.

Not that this is an especially political pop show. Melodrama is a record chiefly concerned with the ins-and-outs of late-teen life, an impressive topic to convincingly delve into give that Lorde’s own journey since the release of Pure Heroine has been anything but typical. She opens, slightly incongruously, with “Magnets”, her collaboration with the similarly short-in-the-tooth Disclosure - whose second album campaign now stands as a cautionary tale about the constant proximity of irrelevance. That isn’t something that’s likely to visit Lorde any time soon. She tears through the emotional wrought of “Tennis Court” and “Hard Feelings” with the verve of somebody who clearly recognises that the chips are finally down - this is a live show that has to go around the world, come hell or high water. She falls to her knees, spotlit, to play the intro to “Buzzcut Season” on a cheap glockenspiel. She doesn’t need these kind of done-with-mirrors tricks to feign intimacy tonight, but she might once she reaches the arenas.

This is a performance in three acts, the first coming to a close right after “Sober”, a wide-eyed and sharp-tongued ode to formative clubbing experiences that underlines the growing-up that Lorde’s done since Pure Heroine. “The Louvre” kicks off the second, and you might forget, with the crowd screaming, how gorgeously she traps young love in amber with the lyrics: “Summer slipped us underneath her tongue” is the initial line, and she goes on to characterise Melodrama’s central theme, obsession, as thick perfume.

“Liability” is the LP's piano ballad, and as much as she rambles on for a good few minutes before playing it, it’s worth noting that amongst all the platitudes, she’s genuinely trying to recount her fraught relationship with her own state of mind to the audience. One of the trappings of her fame is that she’s friends with other pop stars who are happy to live the unexamined life and write about nothing but their own pettiness, without consideration as to how they might make that relatable to the listener. Perhaps they could learn something from Lorde.

There’s probably no need for the Phil Collins cover that closes act two, sharply executed as it might be; we’ve all heard ‘In the Air Tonight’ done to death by now. It proves the prelude to the show's third and final part, and afterwards, we get an incendiary run, one that includes Melodrama’s anthemic standout “Supercut” as well as “Perfect Places” and “Green Light”, the record’s two bookends that also serve as fierce contenders for the title of single of the year. “Royals” is there too, the song about celebrity superficiality that the casual observer might suggest Lorde has rendered void and hypocritical since her ascension to the A-list.

That’d be a thoroughly unreasonable reading, but even if it was true, try finding anybody here tonight who thinks less of her for it. Lorde is twenty years old, and these remain early days for her. On this evidence, the alt-pop crown is hers for as long as she wants it. Her subjects can only hope for an extended reign.