Miley Cyrus, it transpires, is not some post-feminist antichrist sent by an evil music industry cabal to drag young women back to the dark ages. She is merely an obnoxious buffoon in a painful-looking leotard; an extreme pop extrovert with no off switch or edit function – and very funny with it. At one point in a two-hour show packed with cartoon lunacy, Cyrus appears to hump the leg of a giant inflatable effigy of her dead dog, Floyd. (It might just be a hug with thighs.)
At another, she talks volubly, unscriptedly, and with frequent recourse to Anglo-Saxon, about her recent hospitalisation ("bitch nurse stabbing me every two hours"). London is her first date back on tour after a series of cancellations, and her first in Europe since the release of Bangerz, her fourth album. Cyrus confides that she now takes a pre-stage prescription of B vitamins (to pep her up) and lavender (to calm her down). "The lavender's not working!" she yells, bug-eyed.
You don't say. Most pop shows are energetic, but Cyrus is like a Duracell bunny of provocative mischief. She works as hard as her dancers, an equal opportunities crew of multiple hues and nonstandard sizes. They probably do most of the twerking. Cyrus, meanwhile, covers miles, prancing, grabbing her crotch while crossing her eyes, spanking her dancers, waggling her tongue and yakking volubly – the very opposite of the robotic mainstream song thrushes who gyrate for their supper. She proselytises about weed and how best to smoke it ("It never killed anyone!"). She provides a running commentary on her wardrobe malfunctions. She adds the word "cunt" into a cover of Dolly Parton's Jolene (Parton is her godmother) while wearing a bling plaid shirt, and makes an unexpectedly good fist of Arctic Monkeys' Why'd You Only Call Me When You're High?. If there is a message, she is never on it. Cyrus often seems much younger than 21 – an impression helped along by projections of internet cat memes, rude arrangements of sweets, and animations, one notably by John Kricfalusi, of Ren & Stimpy fame. There's more art and more concept here than anyone since Lady Gaga, delivered tonight with an endearing air of neon haphazardness.
It's clear that Cyrus finds sex fundamentally ridiculous – not a thing of power and mystery, but a tool with which to goad the grown-ups. And although Bangerz is full of constant, simulated raunchiness (from an un-pneumatic girl in a boyish crop – this is not insignificant), there is actually relatively little smut. One video interlude, soundtracked by Alt-J, of all people, finds some straight-faced S&M intruding on Cyrus's shrieking teenage sleepover take on titillation.
But performing, she wears cowboy boots. Scratch the surface of Cyrus's synthetic pop 2.0, and there are country values: proper singing – Cyrus's low register is a fine instrument – and patriotism. Cyrus's closer, Party in the USA – an explosion in a flag and glitter factory – is actually far more offensive than the strangely chaste orgy in a giant bed during Get It Right.
More problematic is Cyrus's take on hip-hop – a persistent issue, even after the row that accompanied her VMAs performance last August. When Love Money Party calls for a Big Sean verse, the rapper is represented as a parade-sized cartoon effigy. On 23, Wiz Khalifa and Juicy J are rendered as a blobby video jelly person. Cyrus has been keen to appropriate the accoutrements of hip-hop culture – the beats, the twerking, the golden Hummer with spinning rims that she humps while wearing a leotard made of cash for Love Money Party, a song surely dreamed up by a focus group free-associating superficiality. The considerable consternation about her judgment in the show has not been taken into account.
Usually, the ballads provide the toilet break in any big pop show. Tonight, though, Adore You and Wrecking Ball supply some of the best music, with Cyrus's able vocals foregrounded. For Adore You, she encourages the audience to snog with tongues. When the roving cameras find boys kissing boys and girls kissing girls, a massive cheer goes up, which prompts another impassioned speech from Cyrus in favour of being oneself. If there is a gist to all her shtick, it would probably be this: that no one should feel any shame for being who they are. But it is a shame that her beliefs about self-actualisation are so often illustrated by dry humping.
• Kitty Empire reviews Turn Blue by the Black Keys
