It must be infuriating to have a pithy title bestowed on you by an unbroken succession of music writers – and I will now continue that infuriating succession. Indie artist Beth Orton, due to her position between folk and electronica and sometimes writing from morning-after epiphanies, was known around the turn of the millennium as 'comedown queen', and her music as the ideal accompaniment to a partygoer's recovery, providing continuity with, and an acoustic panacea for, the bright lights and beats of the night before. Reductive then, the appelation has proven inadequate as she's moved to none-more pastoral collection Sugaring Season and her new record Kidsticks which explores the synthetic heart of electronica. As dance-devotional lead single 'Moon' aspires, "I know what the sun feels like on my skin / I wanna know what the moon feels like within", she's plunging us back into the night before.

It's a benignly psychedelic world the album hints at, and the stage-set of huge white balloons evokes an Andy Warhol happening or even The Prisoner. Firstly to their own bank of synths come Brodka, Warsaw's genre-less band of pop sensibilities and retro-futurist attire. They quickly catch the attention with timbres and scales echoing eastern European folk music, and Monika Brodka firing off a guitar solo with the stridency of St. Vincent. A couple of the singles have Florence Welch-esque urgency, and their energetic drummer (made entirely of limbs and hair) never lets the energy flag – but as the set goes on, they sidestep expectations, delaying one song's final verse until we've started applauding, and climaxing on a 70-second-long punk banger and quitting the stage. Defying expectations is something you may want to do after winning Pop Idol, and is apparently best done with pristine harmonies while dressed like a female priest/astronaut.

That may have maxed out the O2's capacity for surprise! But there's quite a bit of anticipation as Orton's trio mount the stage. A musician with whom many here grew up, and who's about to take them somewhere different. The initial brace of new songs works nicely – 'Moon' builds to a rave-like intensity with wonky metallic keyboard lines on the way, and 'Falling' sounds like Kate Bush covering 'Ashes to Ashes'. Then Orton acknowledges the popularity of her first two albums, made a shocking 20 years ago, and reminds us of old times by playing a gorgeous 'Galaxy of Emptiness'. The refrain entreats "Could you please knock me off my feet for a while?", after which tonight's audience need a moment to get back to theirs.

So the evening encompasses Orton's bold new sounds and the 90s-topping old ones, but the twain don't really meet to make a cohesive set. 'Pass in Time' is stunningly raw, but its acoustic-thrumming seems cut from a different cloth to Kidsticks. Another key line is "You can't pin this butterfly down" (from 'Sweetest Decline' – once swathed in 'Raindrops Keep Fallin'-esque strings, as if sounding deeply AOR were her rebellion), as if the pleasure of alighting on different styles is worth sacrificing such paltry currencies as coolness and consistency. Ephemerality is also a recurring lyrical theme, echoed by colourful projections of Super 8 film onto the balloons – a rare occurrence of visuals enhancing, rather than distracting from, onstage performance.

The good news, then – though there have been great things between 1996 and now, Kidsticks showcases a musician with a new lease of life. 'Snow', on record like tUnE-yArDs' mellower big sister, becomes truly epic live; 'Petals' concludes with free-tempo percussive clatter on the album and with breathtaking, purgative walls of noise tonight. Tonight's second excellent drummer ensures that songs reach their intended impact, and the electric guitarist unleashes a couple of melodic Robert Frippesque solos, at one point seemingly forgetting everyone else in the band is present. And Beth Orton's voice is on point – falsetto and Nico-like low-register vibrato are texturally effective, and the pitching is better even than on those documents of the last millennium, Trailer Park and Central Reservation. Orton is enthused, awkward and forthrightly goofy in her banter, even when reminding her audience just how long it is they've been on a journey together. And soon, we all leave to find (a) our slippers or (b) the beginning of a hedonistic voyage of dance and discovery. Admittedly I'm an (a), but I have been knocked off my feet for a while.