The Essex Green, Water Rats, London<br></br>British Sea Power/ The Pipettes, Garage, London

All the leaves are brown, and the sky is grey. And The Essex Green have come to paint London a deep, deep blue. The bleak midwinter may not be quite the most auspicious season to be hearing something as autumnal as the mellow mood music made by this Brooklyn band, but that's perhaps as it should be. The Essex Green are a band out of time (they evoke the late 1960s/ early 1970s) and, if their apparently Anglophile name is any guide, a band out of place too: The Essex Green possess an elegance, and a mastery of poignancy, of which you might, quite understandably, have concluded that the present generation of American bands is utterly incapable.

But they're here in quaint Olde Englande tonight, to headline the first of the Winter Warmers, a three-night stand hosted by Track And Field, the club/organisation dedicated to playing "the music you never hear on the radio" (think post-Cutie, think Bowlie weekender, think Belle & Sebastian, from whose song the collective takes its name).

Central to their charms is the clear, pure voice of Sasha Bell, the singer/multi-instrumentalist who carries herself with the repressed demureness of Katharine Ross in The Graduate, and sings like Michie from The Mamas And The Papas. Bell plays a flute, plays a guitar, plays a Korg keyboard but makes it sound more like a vintage Farfisa, wears a tweed coat of the kind The Supremes' Mary Wilson used to wear (oblivious to the heat, because style is more important than comfort), and never smiles. Every boy in the room is falling in love with her. None of them will admit it.

An Essex Green discography/family tree would be a complicated business: a reshuffled line-up of the same band will play the following night under the name The Ladybug Transistor, and they once recorded a whole album using the alias The Sixth Great Lake. For now, the most important artefact is The Long Goodbye, The Essex Green's full-length hello.

And listening to the album at home is a preferable experience to standing in a sweaty room and watching them (they don't move much): with the exception of the odd surf number ("Lazy May!") from co-vocalist Christopher Ziter, their repertoire evokes The Carpenters at their most bittersweet, Saint Etienne at their most subdued, Jimmy Webb at his most conventional, and the themes to Seventies American TV shows you never saw.

Not that this has prevented many people from standing in a sweaty room to watch them: it's packed in here. "How come," asks Ziter, "it's hotter than when we played here in August?" Once anachronistic, always anachronistic.

The dying hours of 2003, and The Garage at Highbury Corner has chosen an unusual way to see in the New Year. On the face of it, British Sea Power are not the most festive of bands. Then again, there aren't many bands who could start a song with the terror-stricken line "Jesus fucking Christ, oh God no..." and make it feel oddly celebratory.

Since I last saw and reviewed them, British Sea Power have made a stealthy ascent from intriguing oddballs with a fondness for vintage costumes and plastic herons, via a debut album, the cockily (but not dishonestly) titled British Sea Power's Classic The Decline Of British Sea Power, to a growing status as an irreplaceable musical treasure.

The last time I came home from a gig with boughs from a fir attached to my clothing, it was The Smiths 20 years ago (20 years? Kill me now). And their fondness for foliage - BSP have framed the stage with bits of trees - isn't the sole similarity, although it's certainly true that it's been two decades since I've seen vegetable matter swung with such enthusiasm by a crowd.

There's a fervour among the fans which is reminiscent, albeit on a smaller scale, of Smiths-mania. There's a comparable aura of significance about the band themselves. There's the same penchant for dressing in archaic attire (for hearing aids and National Health spectacles, read Second World War helmets and woollen scarves). And singer Yan's eloquent, if not quite verbose, lyrics - the lines about "these island shores", the verses which begin "Oh, little England", the slightly stuffy fascination with "deaths head hawk moths" and the like - and the rhetoric about "benign nationalism" are all inescapably reminiscent of Morrissey.

And, as well as being a highly cerebral band, British Sea Power are - again, like The Smiths - a surprisingly physical experience (one member dives into the crowd with a snare drum on his head, and later so does Yan, now shoeless).

Of course, BSP's music is also reminiscent of Eighties indie rock in general - not just The Smiths, but Psychedelic Furs, Echo And The Bunnymen, Teardrop Explodes and many others - and they instil a now-unfashionable feeling that what they're singing about matters. There's the claustrophobic "Fear Of Drowning", the epic sweep of "Carrion", and the painful honesty of "Remember Me": "Do you worry about your health/ Do you watch it slowly change/ And when you listen to yourself/ Does it feel like somebody else?" British Sea Power are the only band of their kind to recognise the bigger picture, to dare to look beyond the instant thrills of youth, and sing about mortality and decay with a fearless, pitiless clarity beyond their relatively tender years. This is pure guesswork - guesswork is part of my job - but I have a suspicion that Peggy Lee's "Is That All There Is?" and Sinatra's "It Was A Very Good Year" are more important to BSP than, say, Joy Division are.

As midnight approaches, they've almost exhausted their repertoire, and guitarist Noble announces, "If anyone wants to get up and play a song... there's plenty of time." You forget how young, and so far non-prolific this band is (they can't even resort to B-sides: they've already played all of them in an early evening acoustic set).

Later on, three girls in polka dot dresses will take up this invitation, and play a brief set of Hammond organ-based, hi-NRG pop, involving synchronised hand movements and songs which rhyme "ABC123XYZ" with "we don't care about XTC". Apparently they're called The Pipettes and they come from Brighton, but by this point, my alcohol-addled thoughts don't get any more coherent than "Ooh, I like the one in the middle", so you'll forgive me if I defer a proper review until a future date.

All over town, other people were face down in fountains, or getting nostril-deep in cocktails to the sound of Abba tribute bands. But as midnight approached, and a lone bagpiper released his elegiac screech, one felt oddly privileged to have spent the changing of the calendars in the company of a band as bracingly, refreshingly joyless - and paradoxically joyous - as British Sea Power.

s.price@independent.co.uk

The Essex Green: Spitz, London E1 (020 7392 9032), 19 January