A fusillade of marcato strings, a thunderous kick drum, Indian raga chants and Chandrasonic bellowing, “Keep bangin’ on the walls of Fortress Europe”. Thus begins another ADF adventure.

What a silly idea Asian Dub Foundation must have looked on paper: a loose collective of (extremely talented) musicians with an explicit socio-political agenda, whose audio incarnation is only one strand in their interdisciplinary scheme to combat poverty, oppression and racism around the world.

But then the albums started coming out. Facts And Fictions was good, Rafi’s Revenge was very good, Community Music was astounding. The unthinkable had happened: ADF had managed to fuse politics and music at the expense of neither. The songs were angry, polemic, didactic, infectious, danceable and intelligent.

In an ideal world, there would be no attrition for such reckless disregard for the physics of art/morality interactions. But in reality, the Foundation’s occult merger of music and politics is an unstable system. And on Enemy Of The Enemy the cracks are beginning to show.

Sonically, everything’s still in place. Umpteen layers of percussion, some programmed and some live, create dizzying rhythms. Chandrasonic’s hypnotically simple guitar lines get the feet a-tapping as e’er they did. The bass is still seismic. But the melodic transports of Community Music have been replaced by a return to purer, formulaic dub roots which, for non-aficionados like this reviewer, strips ADF of their greatest hook: eclecticism.

There are some great tracks on Enemy, to be sure. ‘Basta’, a brass shuffle with a stumbling 6/4 rhythm, is heady and compelling. ‘19 Rebellions’ employs the collective’s trademark narrative sample, this time an activist recounting a Brazilian prison revolt which was brutally suppressed in 1991. ‘1000 Mirrors’, far and away the most melodic track on the record, features Sinéad O’Connor in superb voice, sounding far more at home with a trip-hop aria than with her recent retro-trad output.

But elsewhere the rapping is too rushed, congested, the backing perfunctory and unmemorable. ‘Power To The Small Massive’ borders on self-parody, as does the deeply contestable syllogism of the title track: “The enemy of the enemy is a friend/So he’s the enemy again.”

The symmetry has been broken. Their politics has overthrown their music. Some decent lyrics survived the coup – “Is revenge the only way that you can make a stand?/It’s not how you fall; it’s how you land” (‘La Haine’) – but in general, the sense of spirituality which in earlier Foundation material informed both their musical and earth-saving machinations, is absent (as is vocalist Deeder Zaman, whose sonorous yelp is sorely missed. Guests Ed O’Brien, Sonia Mehta, Ghetto Priest and Navigator make noble but ultimately futile attempts to fill the space left by his departure).

ADF are better than this album, and a little priority rearrangement – music up, proselytising down – will make the next one a return to form.