Back in the '90s Portishead provided a dour, dislocated soundtrack to the disquiet experienced by Ikea shoppers, selling millions of records in the process. In this, their Third incarnation, the bland comfort zone of that peculiar decade is replaced by the nightmares of today: the war on terror, CCTV, detention without trial, climate change, rediscovery of the Cold War down the back of the sofa|

This is an album evocative of secret military research facilities; soldiers inhuman behind gas masks; those 'golf ball' radar radomes that used to loom over Fylingdales Moor. In short, it's more 1984 than 1994, with Portishead jumping back a decade into a time of insecurity and high tension. Even the song titles " 'Hunter', 'Nylon Smile', 'Plastic', 'Machine Gun' " have an air of abstract alienation to them.

It's a world where, on album opener 'Silence', nature has been industrialised. The beats sound like the clattering of some mechanised horse's hooves. There are digitised tweeting sounds evocative of robot birds at play in a deserted, barren garden. The strings " in Portishead's hands, never soothing " merely accentuate a sense of loss. Rather than the sparse beats and sample-based construction of 'Dummy' or 'Portishead', 'Third' employs a far denser production, with ancient synths, live drums, strings and guitar all vying for space within a precise, determined framework.

Third is a record that comes from a creativity unleashed as much by listening to the likes of psychedelic doom bass madmen OM as Public Enemy (Geoff Barrow explained as much in a recent interview). Whereas much of Portishead's '90s output had the feel and limitations of a film soundtrack " 'All Mine', especially, would have slotted nicely into a Bond flick " Third is a complete, evocative whole. Final track 'Threads' is surely named for the unfathomably grim 1984 BBC mockumentary about Sheffield in the aftermath of a nuclear attack, and for that alone it's a brilliant way to end the album. Adding to its charm, there's a grim perfection to the deep, menacing, atonal booms that conclude it.

Of course, a record of unrelenting misery can't succeed as well as one where the mood varies; and Third succeeds precisely because it's an album that flows as well as ebbs. On 'Plastic', a peculiar and unsettling rattle adds tension, while the Silver Apples drive to 'We Carry On' demonstrates how Gibbon's voice (Ophelia singing distractedly to herself on the way to the river) has grown in textural dexterity over the past decade, even if her lyrics, which are often more personal and fixed in matters of the heart rather than in the abstract overarching mood, are perhaps the only weakness in the Portishead armoury. 'Deep Water', ostensibly a sweet torch song with querulous banjo, sounds terrifying in its juxtaposition with the grinding song that precedes it ('We Carry On') and the brilliantly tense one ('Machine Gun') that follows.

While 'Third' is undoubtedly a dark, unforgiving album, you only have to look at the black-clad thundering legion that packed the Portishead-curated ATP last December to know that while such influences might have shaped this record, this is still a band who wave a scalpel at a very commercial jugular. Burial, say, will give you a more uncomfortable journey around the dark streets of a city at night, Sunn O))) a more stygian gloom, and so on.

Still, respect is due: 'Third' is an unexpectedly absorbing album from a band who've used ten years of exhaustion and disillusionment to hone what was initially great about them before into something entirely new. It'll leave the Sunday supplement types " with their bulgur wheat, falafels and patio heater angst " a distant memory.