British Sea Power, Dublin Castle, London; <br/>The Beta Band, Ocean, London

British Sea Power have a heron problem. They also have an owl problem, a crow problem and a stag problem. Where, in a venue as small as the Dublin Castle, will they manage to fit the assortment of taxidermised fauna which provides moral support at their shows? There's a pleasing whiff of intrigue about this band. Before the Lake District-via-Brighton quartet even appear, the stage is "dressed" in branches covered with tinsel, not by hairy-backed roadies in faded Soundgarden T-shirts, but by three young women dressed as Russian peasants.

Such attention to detail is vital if you intend to transcend the surroundings of the indie dive (walled with black tar, floored with congealed lager), and it creates a suitably magical, Narnia-like context for what follows.

The wonderfully-named British Sea Power will never be million sellers, but they will sell their name to HM Government for a million in a decade's time when the gas fields dry up, which frees them to pursue their singular vision without concern for commerce. They have been known to arrange interviews by giving an Ordnance Survey reference number as a rendez-vous, they occasionally wear First World War uniforms at their shows, and they exude deliberateness, sobriety and propriety (their shows are described not as "gigs" but "concert engagements").

In the current climate, this alone is so precious that actually hearing them, you fear, might be a letdown.

When they take the stage and take up two guitars, a bass and a drumkit – the same instruments the Beatles used, for heaven's sake – there's every danger the spell is about to be broken.

Four emaciated, bony-cheeked young men who could do with a home-cooked meal, they peer at us over their microphones with lizardly, lidless eyes, interested but impassive, as though we're fish in a tank. As soon as the music begins, all doubts are decimated: their angular, artful rock (as opposed to "Art Rock") shimmers bright and shudders hard.

Singer Jan Scott, whose face has a touch of James Woods and a smattering of Richard Bacon about it, stares maniacally throughout and never smiles. Neither do the dual guitarists Neil Hamilton (despite nominal differences, Scott's brother) and Martin Noble, both of whom are wearing what appear to be white BNFL anti-radiation suits adorned with seagull feathers. I can't see drummer Matthew Wood, but somehow I don't think he's grinning either.

There's a new seriousness at work here. It's unclear exactly what BSP are serious about – their clandestine obsessions appear to be Mitteleuropa, ornithology, military history and highbrow literature – but whatever it is, they're deadly serious about it. Intense and unashamedly intellectual (their most popular song, new single "Remember Me", has the word "increment" in the chorus), British Sea Power are reminiscent of the smarter late Seventies New Wavers like Joy Division, Pere Ubu and Talking Heads (Jan's vocals have a whoop and stutter that's very David Byrne), and the late Eighties/early Nineties generation (an unslack Pavement, or a sexless Pixies). Excellence is in their crosshairs. It will soon be theirs, mounted on a wooden plaque.

When the smoke clears, what sort of monster do you turn into? Now, I enjoy a semi-legal social puff as much as the next multiple sclerotic café proprietor, but the culture that usually goes along with the old Mary Jane makes me heave. First you're watching crap films on Channel 5, then you're eating cold pizza with the consistency of pillows, and before you know it your vocabulary has granted admission to words like "doobie", "toke" and "roach". It's a slippery slope, and The Beta Band, whose latest album Hot Shots II is actually named after a crap Channel 5 film, are somewhere near the foot of it.

Through a stoner haze, The Beta Band have reassembled pop in much the same way that the Renaissance academic who couldn't translate English to French, but could translate English to Portuguese and Portuguese to French, compiled the first English-French dictionary. On (Rizla) paper, this sounds like an excellent idea. In practice, they're Super Furry Animals without the ability to connect.

Tonight's show is supposed to be a fancy dress occasion, but the word has only partially circulated. There are a few lads with skirts over their jeans, lots of joke shop pink wigs, one Lt Uhura, and one giant green insect. The Beta Band's efforts in party décor are similarly half-arsed: four confetti-filled balloons, a couple of helium crescent moons and a string of paper flowers. Up on the three back-projected video screens, we see the band take a cheapo blue-screened magic carpet ride over sports stadia, exotic beaches and the NYC skyline, and crappy camcorder footage of the band playing motorbike computer games.

Steve Mason tells us off for being too quiet, but if he can't get the party started, why should we? Mason's own face is a picture of neglect. It's covered in the sort of stubble that's more dole queue than designer. Wearing a white towelling bathrobe and a beanie hat, he's oddly reminiscent of Eric Stoltz's drug dealer in Pulp Fiction, the one who couldn't even be bothered to get dressed. The keyboardist and drummer, at least, are in costume, as minor F1 drivers who haven't managed to attract enough sponsors to cover their torsos. The bassist is wearing, you know, some clothes.

Even with your eyes closed, The Beta Band's subaqua baggy (New Fast Automatic Daffodils are a close comparison) rarely excites. Keyboardist John Maclean jumps up and down with enough energy to suggest that he, at least, is on something less herbal and more chemical, and the rare moments of musical prettiness come from him. When he blows into a school music-class melodica, and trumpeter "Neil" joins in, they occasionally work up a critical mass, almost attaining the haphazard momentum of early Mercury Rev, but Mason's smoke-tightened monotone has the deadening effect of the world's worst skunk. The Grange Hill crew got it right: Just Say No.

s.price@independent.co.uk