IoS pop review: Alt-J, Concorde 2, BrightonPoliça, Concorde 2

The man they tried to ban gives his grudge-free opinion of this year's Mercury Prize-winners

Someone in the smoking area recognises me. "They let you in, then?" they shout. I laugh and walk towards the door, head down. I'm not counting any chickens yet.

Why? Let's recap. Tuesday 30 October 2012 was one of the more interesting days of my journalistic career. I'd spent the afternoon lecturing students at Solent University about the importance of critics developing independent voices in the face of efforts by the music industry to manipulate them.

Job done, I began the long journey to Norwich, where I was due to review Alt-J at the Waterfront, hotel booked, train ticket bought, and I'd been added to the guest list by the band's PR.

At 4.10pm I received a phone call from that same PR. In the precinct outside Southampton Central, I listened with disbelief as he told me the Alt-J camp couldn't let me into the gig after all. "Can't, or won't?" I asked. "Won't," he was honest enough to admit. Half an hour earlier, I could have put the call on speakerphone to show the entire lecture theatre the sort of nonsense I'd been warning them about.

The reason for banning me, it transpired, was a tweet I'd made. Having heard the band tell BBC 6 Music's Lauren Laverne about their name – a triangle, or Delta symbol, pronounced "Alt-J" because that's the keyboard short cut for the shape on the Mac – I wrote: "I'm kind of appalled, but also appalled at myself for being appalled." As a man with the Prince symbol tattooed on my bicep I felt it only fair to confess my inconsistency. But no, apparently the poor dears' fragile egos were wounded, and couldn't bear a brute like me to review them.

At this point, you may wonder why I didn't just turn up and buy a ticket. One, it was sold out. Two, writing about gigs is my job, and I'm guessing you'd bridle if asked to pay admission to your place of work. Plus there's an unspoken mutual understanding between PRs and press that in order for us all to do our jobs, journalists must be allowed into gigs. PRs know that if they want us to write something nice about their other acts, they have to take the rough with the smooth. That's how it works.

Now, if Alt-J want to buck the system, that's their prerogative. But you can't have it both ways. Just two days after their attempt to muzzle a critic, Alt-J accepted the Barclaycard Mercury Music Prize for their debut album, An Awesome Wave. And you know who chooses the Mercury Prize? Well, in part, it's industry bigwigs. But it's also a cabal of newspaper critics. Like – but not, I hasten to add, including – myself.

Hilariously, in the pre- and post-ceremony coverage, Alt-J not only thank "everyone back in Harrogate" (they're widely presented as a "Leeds band"), and affect uncertainty as to whether they even want to win, but also make the astonishing claim that "we're not worried what people think".

My experience suggests otherwise, and I made damn sure that the world knew about it. Like a dog with a bone, I wouldn't let it go, and tweeted all day about what I saw as the band's hypocrisies. (Eventually, the following Monday, a boss at their label would call me to apologise, taking the blame himself. He may or may not have been jumping in front of a bullet for his boys. We'll never know.)

You see, unfortunately for Alt-J, we critics aren't just there to give awards. We're also there to tell the truth. And, as luck would have it, three days after Mercury night, Alt‑J were playing on my home turf, where I have contacts, and any desire to interfere with press freedom would be powerless.

So, I enter their Brighton gig almost determined to give them a positive review, just to prove a point. But honesty must prevail, and I emerge as noncommittal as I went in. Alt-J are neither terrible nor brilliant. They're a quartet of post-Radiohead postgrads, at least two of whom should wear the caption "God help us if there's a war" around their necks, who specialise in shuffling mid-tempo beats, noodling filigree guitar work, weedy falsetto vocals, and vaguely pseudy lyrics with cryptic allusions to hay fever drugs and harpoons, who perform in front of the sort of neon triangle last seen on Gary Numan's Pleasure Principle tour, and who throw a mash-up of Kylie's "Slow" with Dr Dre's "Still Dre" into their set. They're all right, I suppose. Now, was that so painful?

If you had to guess where Poliça are from, given their echoes of Lykke Li, Little Dragon and Niki & the Dove, you'd take a stab at Sweden. And, given that they hail from Minneapolis, which is the most Scandi-fied state in the US, you wouldn't be far wrong. Formed by Ryan Olson and Channy Leaneagh, both sometime members of soft-rock revivalists Gayngs, Poliça – the name is a mis-spelling both of a Polish mountain where a plane crash took place and the Polish word for policy – make perfectly pleasant electro-indie pop with no apparent passion or intellectual force behind it. You find yourself contemplating the peripherals, like the way the lights throw a purple swastika on the wall, or the fact they have two drummers, like the Glitter Band or the Ants, or the way Leaneagh looks like Anita Harris or Una Stubbs playing principal boy in a 1970s panto. You're startled out of it only when she breaks the monotony with some autotuned a cappella folk singing.

Again, they're all right, I suppose. But if Alt-J and Poliça are really the best the British and American indie scenes have to offer in 2012, then both nations will need to buck their ideas up in 2013.

Critic's Choice

The runaway popularity of rootsy soul-rockers Alabama Shakes, fronted by Brittany Howard, has far outgrown the early hype. They make another UK visit, stopping off at Academy 1, Manchester (Mon); Barrowlands, Glasgow (Tue); Olympia, Dublin (Wed); and London's Coronet (Fri) and Forum (Sat). Meanwhile, the evergreen Squeeze, with a BBC4 special in their rearview mirror and a new album due next year, begin a UK tour at G Live, Guildford (Fri); and Corn Exchange, Cambridge (Sat).