The Mercury prize for 2012's best British album is awarded on Thursday. This means the season for complaining about the shortlist is nearly over and the brief window of griping about the winners is about to open. This year's field has overlooked known quantities (Kate Bush, Dexys) for debuts by fresh meat, resulting in a greater than average "whuh?" factor surrounding the list.
Mindful of that, perhaps, the Mercury people have put on a series of gigs by the nominees, all filmed for broadcast on Channel 4. This moving shop-window is a slightly artificial atmosphere in which to savour a band. No one will crowd-surf, heckle or swear. But in the glare of lights, with pin-sharp sound, there should be nowhere for their music to hide – a situation that ought to favour the favourites, Alt-J. Leading the pack at 5/6, the Cambridge-via-Leeds University quartet make tricksy electronic rock whose digital textures are scalloped with the care of surgeons. Ladbrokes dubbed them "the new Radiohead", which, you might argue, is like George Osborne coining a new strain of post-dubstep.
Alt-J's debut, An Awesome Wave, went into the top 20 on release in May, a rare feat, especially for an unknown guitar band. Radio 1 DJ Fearne Cotton plays their singles and now they find themselves "the most talked-about band in Britain", according to this week's NME. "How the heck did that happen?"
By singing strangely, it seems. Tonight Alt-J's vocal stylings swing from folk harmonies to what can only be described as stalker-soul. Well into their set, their single, Breezeblocks, finds Joe Newman describing a woman's murder in a creepy, affected, nasal sing-song: "hold her down with soggy clothes and breezeblocks," he croons. The online video for the song is – cannily – run backwards. People play it again and again to figure out whodunnit, thereby boosting Alt-J's YouTube views.
An a cappella passage, voiced by an eight-piece backing choir, introduces Tessellate, ostensibly about geometry, sex and being fed to sharks. "Triangles are my favourite shape," sings Newman, barely less creepily than before. The band's name refers to the keyboard shortcut for a delta on Macs.
Throughout Alt-J's set, accessible folky elements offset the complexities of their instrumentation; as the set winds on, passages of unadorned guitar provide relief from all that trying so hard. Mumford & Sons have recently covered Tessellate, underscoring an unlikely continuity between the bands.
Alt-J's only appealing experiment comes on the closing Taro. The song considers the love between photographers Robert Capa and Gerda Taro; meanwhile, bassist-turned-guitarist Gwil Sainsbury unleashes an Indian string flurry from his guitar by playing it with what looks like a castanet.
Headliners the Maccabees sound heroic in comparison. Having begun life as a jerky indie band in debt to the Futureheads, they have matured into a force which pits three guitars and massed effects pedals against the coy mumble of singer Orlando Weeks, all delivered through vintage Selmer amps. Weeks is a nervy, brooding figure, with the endearing habit of hiding his hands inside his pullover cuffs when not playing his guitar, as though in fear of giving too much away.
At 12/1, the Maccabees are the Mercury's indie rock meat-and-potatoes option, if that doesn't do a disservice to their latest searching, surging incarnation. After a few bars, a beefed-up version of Feel To Follow gallops off towards the kind of well-drilled catharsis that's the proof of a band who've been touring heavily.
On release last January, their third album, Given to the Wild didn't quite live up to all the praise heaped upon it. But the tunes have gained in authority as the Maccabees have headlined venues like London's cavernous Alexandra Palace, and their mix of swagger and sensitivity has grown more convincing. Given to the Wild is concerned with childhood and growing older, and the night ends with the shimmery quiver of Grew Up At Midnight – an antidote of hopeful innocence to the calculations of Alt-J.
