By Mark Beaumont

Copyright independent

“Kneecap at Wembley,” beams Mo Chara, “Keir Starmer must be raging.” And the rumble from the Belfast rap trio’s second ever arena gig might well be echoing through the obsequious banqueting halls of Westminster. Because from the Palestinian flags hung from the arena balconies and the heartfelt chants of “Free, free Palestine” rattling the rafters whenever the cause is mentioned, it’s clear that in the space of one turbulent summer Kneecap have evolved from semi-serious agitators into a genuine political movement.

Since Chara – a very vocal supporter of Palestinian freedom, alongside bandmates Móglaí Bap and DJ Próvaí – was charged in May with displaying a Hezbollah flag onstage in London last November, Kneecap have consistently proclaimed the legal case against him as a “distraction” from the ongoing situation in Gaza. If anything, though, the charges have had the opposite effect, galvanising widespread support across the musical spectrum for the suffering Palestinian civilians.

The summer’s festivals were awash with acts declaring solidarity with Kneecap’s sentiment, if not their specific actions – fellow Irish band The Mary Wallopers even had their set cut short at Victorious Festival for displaying a Palestinian flag. Earlier this week, this very arena saw Brian Eno curate a four-hour Together for Palestine concert featuring Paul Weller, Damon Albarn and a vast array of actors and artists; tonight, Massive Attack screen a film before Kneecap’s set drawing parallels between South African apartheid and current events, and calling for boycotts and sanctions against Israel, then take to the stage themselves to denounce “the weaponisation of the criminal justice system” against the headliners. Whatever the legal outcome, a band that came to prominence just last year – thanks to second album Fine Art and an acclaimed Michael Fassbender-starring biopic – as a self-styled “tongue-in-cheek” merging of youth culture hedonism, Irish republican tubthumping and confrontational Troubles imagery, have now become the focus and fulcrum of pro-Palestinian protest, and arguably the most potent and subversive political force in British pop culture since the Sex Pistols.

Naturally, they triple down. Even before DJ Próvaí rises from beneath the decks like a balaclava’d messiah for their dubby trap opener “It’s Been Ages”, the show opens with an on-screen statement accusing Israel of genocide and the UK government of complicity. Bounding on to a hero’s welcome, Chara and Bap liberally pepper the night with chants – “Free Palestine!”, “F*** Keir Starmer!”, “You’re just a s*** Jeremy Corbyn!” – and comments decrying “awful c***” Trump (“release the f***ing files!”), the Windsors (“talking of paedos, f*** the royal family!”) and the music industry’s isolation of bands speaking out on Gaza: “It’s always the artists that spearhead these kinds of campaigns and movements,” says Chara, “all we’re doing is filling a void that the politicians aren’t filling.” After premiering an intense dark-rave unreleased track beneath a screen full of prison-wall visuals, he makes a public case for the defence – “I’m not the first and I won’t be the last Irishman up in a court in London on trumped up charges,” he says. The word of the day is “unbowed”.

Musically, they’re just as fired up. From a dub-heavy yet playful opening – “Fenian C***s” documenting casual sex across the Irish political divide, accompanied by cartoons of balaclava-clad bikini girls; “Better Way to Live” bouncing by with Fontaines DC’s Grian Chatten delivering its killer chorus from an on-screen TV – they accelerate towards the mid-set, barking Irish-language rhymes like attack dogs. Here, “Sick in the Head” is as pounding and relentless as the bad thoughts it describes, “Your Sniffer Dogs Are S****” is pure demon disco and “I’m Flush” a ferocious rap howl, sounding very much like a song about taking a week’s wages’ worth of drugs in one go and the closest they’ve actually come to detonating a car bomb.

It’s the same show they’ve swiftly advanced from Academy-level venues, and it feels a little swamped by the arena, at least until rave, techno and drum’n’bass beats arrive to kick things up a notch for “I bhFiacha Linne”, “Guilty Conscience” and a sledgehammer “Sayonara”. But the weight of recent events fails to crush the comedy from a house-flecked “Get Your Brits Out” – imagining a narcotic night out with prominent members of the DUP – or temper Kneecap’s sense of fun. “This is my grandmother’s favourite song on the album,” Chara says of “Rhino Ket”, while Bap sings a chorus of Mousse T and Tom Jones’s “Sex Bomb” and Próvaí advertises his alleged OnlyFans account with a flagrant flash of nipple.

For the time being, though, Kneecap are a cause as much as they are a wild night out, and politics inevitably anchors the show. They end closer “The Recap” – their bite-back against vocal critic Kemi Badenoch – standing behind a Palestinian flag and shouting “F*** the British government!” Silence, it seems, is not an option.