At some point in the past decade, a young Danish creative stuck two of her initials together to create a moniker that, in Danish, doubles as the word “maiden” or “virgin”. In time – and it would take a couple of incarnations – Mø would become widely mispronounced.

As with Björk, English speakers – including ticket touts for tonight’s gig – see an “ø” and say “oh”. And so 29-year-old Karin Marie Aagaard Ørsted Andersen – bouncing around in athleisure, a tracksuit top wrapped around her waist – is now widely known as “Moe”, rather than “Murr”. Online, her byline is MOMOMOYOUTH, further muddying the waters. Moreover, there are two distinct halves to Andersen’s career – the hugely listened-to featured artist, and the lesser-known, faintly leftfield pop auteur. It is an imbalance which 2018 is supposed to redress, if all goes to plan.

Having an unpronounceable, tricky-to-type name, an alias and two strands to her work has, somehow, turned out not to be a major branding fail for Andersen. Glyphic monikers have always lent mystery; search engine optimisation means that idiosyncratic spellings can be a boon in the online clamour. People’s Twitter or Instagram feeds often go by a nickname, from @champagnepapi (that’s Drake) on down.

It’s not a stretch, then, to imagine that read as “M.Ø.”, the name hints at something of a modus operandi too, so successful has Mø been at cracking the upper echelons of pop while retaining some core waywardness. A punky teenager, her previous outfit, MOR, played stroppy electronic tunes called things like Pussy in Your Face (2008). There are still tangible traces of that attitude in Mø tonight, ending her UK tour with a mammoth set heavy on newer songs, and no lack of energy.

Before she was bolshy and emo, Mø was a Spice Girls fan who took their “girl power” at face value. So there are faint vestiges of Sporty Spice too, as Mø bounds around, gripping the mic and punching the air more like a rock star than a pop performer. The night is high on hits, but low on other pop signifiers: zero choreography, zero dancers, zero confetti cannon, no costume changes. (There are video backdrops, a new addition.).

There remains an intriguing tension at play in what Mø does: it’s pop, but it’s also, often, not all that pop. Horns (canned ones) often figure in these songs, accompanied by black and white footage of just-so girls playing saxophones; you don’t get that with Miley Cyrus. Tonight’s first track is relatively new: the brooding Roots, from October’s When I Was Young EP, has sultry, jazz-noir overtones; it is rather a departure from those huge EDM-meets-tropical pop confections she is most famous for.

Ultimately, many people are here because, in 2015, a song Mø sang – Lean On by Major Lazer & DJ Snake – became the most-streamed track of all time on Spotify, “all time” being millennial-speak for, “since a few years ago when streaming became a thing”. Still: it was no paltry achievement; in 2017 that track was one of just four songs to have hit 1bn streams (another was @champagnepapi’s ubiquitous One Dance). The effect was rocket-like, catapulting Mø out of her reasonably successful milieu – her own fetching debut album, No Mythologies to Follow (2014), had both critical traction and a burgeoning audience – and into global renown.

Moreover, Mø was not just the bought-in token female singing the hook (and writhing around in the video) of Lean On. She was one of its writers. As #MeToo, and recent court cases involving Taylor Swift and Kesha attest, the entertainment industry is a predatory snakepit, an ecosystem in part attributable to the disproportionate control exerted by men on the means of production. Norse teen Sigrid’s timely breakout hit of last year, Don’t Kill My Vibe, was inspired by her experience of being patronised by older male industry figures. There is still a long way to go, but the plethora of writer credits by artists like Mø (Charli XCX is a major player here) are finally making some inroads into that old model.

For good (it has made her famous) and perhaps, ill (she still struggles to escape the G-force) Mø hit it off, professionally speaking, with Major Lazer hit-maker Diplo; he became a significant presence on her biggish 2015 single, Kamikaze, which gets a surge of love tonight. More recently, the two combined for another earworm of a tune, Get It Right, which came out in November. You can level all sorts of accusations at Diplo – cultural appropriation being a popular one, for this DJ who has mined every continent for sounds – but these big, dramatic tropical pop/EDM/R&B fusions really shake a room; there are mass outbreaks of dancing.

Moreover, Mø’s vocals rise to these big occasions tonight – not just audible, but pugnacious and elastic over the din of live drums, live bass-or-guitar and a hub full of electronic gear. Mø’s continued employability as a featured artist (she’s done loads) hinges on this very versatility – she can do R&B cadences, not just the gauzy Europop of her early work. With that, Mø also brings a hard-to-define swagger, only emphasised when Andersen cut her long hair off mid-2017. Of all the somewhat interchangeable female voices in pop, Mø stands out.

What, then, of her own output? Mø’s putative second album has been delayed for so long, it almost doesn’t matter any more. There are mixtapes, there are EPs, there are “projects”; Charli XCX puts things out as and when.

This tour strives to reintroduce Mø as a standalone artist, and only partially succeeds. You get the feeling that, having got used to hugeness, Mø isn’t going back to her No Mythologies sound, which is logical, if perhaps just a bit of a shame. Tonight we get the light and shade of the rest of the When I Was Young EP, and a couple of new tracks, nestled away.

Thematically, When I Was Young takes MOMOMOYOUTH’s young maidenhood and recasts it into long Scandinavian glances backwards at when she was really young. The title track might not have garnered quite as many streams as the Diplo co-write juggernauts but it’s not doing too shabbily (4m-plus YouTube views). Nostalgia, meanwhile, is a sung-talked tune about an early infatuation that, yes, brings out the tropical pop once more, but with a persuasive catch in Mø’s voice. Mercy – a new ballad – lacks any audible idiosyncrasies.

Ultimately, it will take a definitive piece of work – a second album, say – to finally bring together the swirl of cross-currents that make up Mø, a composite pop star. For now, though, her swagger is just about enough.