Like their fellow reformees Refused, At The Drive-In fell apart before the dust surrounding the release of their greatest work had settled. If both bands seem uncharacteristically joyful in their reformed states, maybe it’s because they have finally realised the significance of their achievements, now that they aren’t mired in interpersonal acrimony. It certainly seems that way as Cedric Bixler-Zavala grins and swings his microphone stand out across an ecstatic Brixton crowd. Later on, Jim Ward will gesture across the stage at his bandmates and tell a momentarily subdued audience: “I love these guys” and you really, truly feel the import of those words.

Earlier, before At The Drive-In’s arrival, comes support from the much-praised Mmoths. At times Jack Colleran’s dreamy chillwave manages to wash through the crowd, but for the most part there is a sense of water lapping a distant shoreline, while the majority here await a tidal wave. As support acts go it’s a surprising choice (not the last of the evening) and one that probably has more to do with Cedric Bixler-Zavala or Omar Rodriguez-Lopez than it does with the rest of the band.

Equally Mars Volta-esque is the cinematic bombast of At The Drive-In’s arrival to the accompaniment of Ride of the Valkyries. Swapping TMV’s A Fistful of Dollars entrance for Apocalypse Now, the band step onstage to hysterical, earsplitting noise from the Brixton crowd. “Good Morning Miami!” yells Cedric Bixler-Zavala before the thunderous toms-and-bass intro of ‘Arc Arsenal’ rumbles forth with all the force and recklessness of Lieutenant Bill Kilgore’s 9th Air Cavalry.

“I must have read a thousand faces!” screams Cedric Bixler-Zavala, and five thousand faces scream back at him, seizing their chance after more than a decade of wondering. When the reunion announcement finally came it represented a surprising about turn after plenty of bitter words. No doubt there were some big bucks behind their decision to give it one more go at Coachella this year, but tonight - possibly At The Drive-In’s final final farewell - you get the sense that the financial payoff would have to be immense to compete with the emotional one. As the Texan band always have done, tonight they work to defy expectations.

Many people here have obviously waited a long time to hear ‘One Armed Scissor’ in the flesh (a rapturously received reward that brings tonight’s show to a close), but they are reminded that At The Drive-In’s incorporation of more disparate elements – the tetchy, paranoid hyper-dub of ‘Enfilade’ or the cultural-death slow march of ‘Non-Zero Possibility’ for example – also play a vital role in marking this band out as singularly talented and their music as something groundbreaking.

Perhaps the biggest surprise tonight is the amount of time the band dedicate to older material. Unlike the Relationship of Command-heavy show they played at Reading the previous Saturday, almost half of tonight’s sixteen-song set is drawn from In/Casino/Out and Vaya. The change is a welcome one; ‘Pickpocket’ and ‘Chanbara’ serve as a reminder of the odd punk genius that first caught the Beastie Boys’ attention, while ‘Rascuache’, ‘198d’ and a breathtaking ‘Napoleon Solo’ prove that behind the band’s creativity was an ability to imbue a chorus with an overawing level of significance and beauty.

When Ward says that the band “see this as the last date on the Relationship of Command tour”, you get the impression that he’s not necessarily hinting at more tours or new music, rather that he’s keen to remind those at Brixton tonight that Relationship of Command makes up only one chapter of At The Drive-In’s history - not that it feels like anyone here tonight hasn’t found time in the last twelve years to brush up on the back catalogue.

None of this is to say that tonight’s show is the faultless (possibly) final act that some might have hoped for. The mix isn’t always kind to the band’s sound – at times guitar lines struggle to break through and Tony Hajjar’s drums are far, far too loud - while Bixler-Zavala’s tendency to almost exclusively employ his latter day near-falsetto will have irked some; while it imbues some of his more subdued vocals with greater impact, often at more frenetic moments the frontman’s lines are yelped, when previously he would have barked.

If Bixler-Zavala is determined to perform on his own terms, it seems Omar Rodriguez-Lopez is barely willing to be here at all. Amid the storm of afros, maracas and Jools Holland-baiting of Relationship of Command-era performances, it was easy to forget that this band was primarily Bixler-Zavala and Ward’s baby. If Rodriguez-Lopez looks awkward back with his old band, it might be because it’s not really his band at all, not in the way that The Mars Volta is. Still, with all that At The Drive-In have achieved as a five-piece, the sight of Rodriguez-Lopez hunched by his amp with his back to the crowd for much of the set is a sad one.

But then, expectation is the hazard of any reunion. Tonight At The Drive-In pay it no heed, eschewing nostalgia in favour of a performance that (for better or worse) is reflective of their current selves as much as anything that has come before.

“This is forever” goes the almost-whispered and then bellowed refrain of ‘Napoleon Solo’, and tonight it feels like these songs are. Some will no doubt have expected a point-by-point retrospective, but that was never likely to happen. At the height of their power At The Drive-In were incendiary, chaotic and uncompromising - unsustainably so. While the band aren’t as explosive as they were twelve years ago (how could they be?), they remain gloriously unpredictable - and very, very special indeed.