I have never found Brighton’s British Sea Power to be interesting at all. They began as one of dozens of vaguely nostalgic bands given a second look by labels in the wake of the Strokes/White Stripes anything retro-rock explosion of the early naughties. Their 2003 debut The Decline of… garnered them many comparisons to Joy Division and the Pixies, albeit a sober and unperturbed amalgam, with more angular riffs than you can cut your wrists to. Open Season of 2005 cut down the angst and landed on The Cure does Prozac turf, while 2008’s Do You Like Rock Music was so much like an overdramatic yet watered down All That You Can’t Leave Behind that Pitchfork famously rated it a U.2/10.

There never has been anything truly challenging or groundbreaking and original about this band, from its opportunistic pastiche beginning to its current edgeless Edge stadium rock facade. The guitar work throughout their career has always sounded safe to the point of being disinterested, as if they recorded their albums while watching TV. Scott “Yan” Wilkinson’s lame-duck vocals—which land somewhere between Richard Butler of the Psychedelic Furs and David Bowie but without the poetry or intensity of either—give the predictable song structures no help. Each album is like a collection of prospective advertising jingles.

Of course, none of that has stopped the UK public from buying more copies of each subsequent release. Alongside the nickel-hacks in Kings of Leon, they proved all you have to do to get a top 10 record in Britain is rip off U2’s sound and add a dash of the Strokes. Everything I have mentioned so far actually makes the latest British Sea Power project that much more remarkable. Instead of investing their energy into milking the formula for Billboard chart success, they decided to take a little time off and produce a soundtrack.

No, they didn’t choose the new X-Men or anything trite like that. They were asked and happily agreed to make a new score for the 1934 docufiction Man of Aran for its special 75th anniversary DVD release. The film more or less documented life as it was for the rustic, pre-modern people of the Aran Islands off the western coast of Ireland. From fishing off high cliffs to potato farming on flimsy soils, the film mixed authentic footage with fabrications of cultural practices from the late 1800s (namely, an antiquated shark hunt that was reportedly out of use for half a century before the original film debuted).

This allowed the band to approach the album differently, with a mind for timelessness rather than instant success. As a result, it is by far their most engaging and moving work yet. Thankfully, it’s mostly instrumental, with only a couple tracks featuring anything resembling vocals, but more importantly, it’s not based solely on working towards and elaborating big hooks. Every selection is allowed to grow and breathe at its own pace, starting off at mournful whispers and drifting towards ecstasy.

The sonic textures explored by the guitars are more dense and varied than ever before, often swirling around in vague distortion before coming into focus on a choice riff at the perfect juncture. This pairs amicably with Wood’s tribal drumming to propel the score, while strings and the odd ambient effect add an elegant atmosphere to each movement. The soundtrack is akin to the closing “We Close Our Eyes” from Rock Music, only with a little more purpose and none of the schmaltzy lyrics.

At the end of the day, the likes of Mogwai, Kinski, Mono, and Sigur Rós all do this kind of music better. This is the ground those guys were born to walk on, while the new Man of Aran score can be a bit of a stretch at times. Nevertheless, props are due for the effort as I shudder to think where they could have gone with it. At least they tried.

• Multiple songs MySpace