From this writer’s viewpoint, Massive Attack were indisputably one of the greatest groups to emerge during the nineties. Their live shows were brilliant, their videos were brilliant, and last but certainly not least, their music was brilliant. Oh boy, was the music amazing.

To hear, say, the soaring soul of ‘Unfinished Sympathy’, simultaneously the essence of melancholy and the most uplifting thing you’ve ever experienced, or, at the other end of the spectrum, the sublime nocturama of the phantasmagoric ‘Black Milk’, is to experience music at its most earth-shatteringly powerful.

Given that Massive Attack’s three albums to date are positively crammed with such moments of sonic bliss, they were always bound to have a tricky task navigating their way into the next phase of their career. Throw in the usual wild cards fate likes to play – Grant Marshall’s sabbatical from the group, Neil Davidge’s rumoured peripheral involvement during recording, and the not-insignificant fact that a full five years have passed since Mezzanine – and you get some idea of the scale of the challenge the band faced.

Nonetheless, by the time the album shuffles into life with the opening ‘Future Proof’, it feels like Massive Attack have never been away. The fractured, Bowie-like cut-up lyric, courtesy of Robert Del Naja, strongly recalls the jaded urban ennui of OK Computer (a record MA once planned to remix in its entirety): “Borderline case/Reinforced glass/Absent friends/Passport photos and borrowed clothes.”

Musically, the track utilises the sort of foreboding atmospherics Massive Attack are masters of, and the overall feel is like driving through some desolate cityscape in the dead of night, with only late-night radio and a smouldering sense of regret for company. It’s a hell of an opening.

Unfortunately, the plot swiftly unravels with the following tracks, ‘What Your Soul Sings’ and ‘Everywhen’. The former is the first of three numbers to feature vocals from Sinéad O’Connor, and while it’s a pretty tune for sure, its warm electro wash lacks punch and vigour. Similarly, ‘Everywhen’ has long-term collaborator Horace Andy set adrift on a dour, unimaginative trip-hop soundscape, and in the line “The stars are like tears”, contains a simile even Mick Hucknall might balk at committing to record.

O’Connor’s subsequent contributions, ‘Special Cases’ and ‘A Prayer For England’, are symbolic of, respectively, what’s right and what’s wrong with 100th Window. ‘Special Cases’ is the first single and possibly the stand-out track, with soaring Arabic strings orbiting a bass-line summoned from the depths of HP Lovecraft’s imagination.

‘A Prayer’, on the other hand, is Massive Attack by numbers, and sees O’Connor lapsing into her most insufferable guise - the whinging earth mother: “By the power of the Holy Spirit/Let not another child be slain/Jah help us”. Jah help us, indeed.

In conjunction with the eight minute ‘Butterfly Caught’ – another listless attempt at capturing that trippy 4am mood – ‘A Prayer’ threatens to turn the listener off altogether. At the last minute, though, Massive Attack manage to redeem themselves. A twenty-minute suite of bruised but defiant ambient hymns, the final three tracks on 100th Window just about prevent the record from sliding into mediocrity.

‘Small Time Shot Away’ is a space-age nursery rhyme for a troubled mind (“It’s my favourite chloroform/It’s pill-talk everytime”), ‘Name Taken’ metamorphoses from slight beginnings into a beautifully plaintive dub workout, whilst ‘Antistar’ returns to Massive Attack’s perennial theme of seeking relief from emotional depletion – “Can you lick my wounds/Can you make it numb/Kill the pain like cortosone/More sweet narcossis”.

It’s fitting that the record should end on such an ambiguous note. 100th Window is a good album. But given the stratospherically high standards Massive Attack have set themselves over the years, the simple fact that this album is not a masterpiece provides ample grounds for disappointment.