Gang of Four, Macbeth, London

Just three songs into the Gang of Four's "secret" show at this tiny pub in London's trendy-but-shabby Hoxton, and vocalist Jon King is swinging from the lighting rig and howling gleefully. Is this any way for a man in his fifties to behave?

Well, yes – not least through the sheer relief at once again experiencing music that combines the rugged brutality of late-70s punk-funk with the bitter acumen of eagle-eyed political criticism, a combination that's been in fairly short supply in recent years. As pop's front-line political activism has been shunted into weed-strewn sidings in order to allow the express train of celebrity-charity activism to speed on unhindered by debate or analysis, it's obvious that something noble has been lost from rock music. The Blairite hand-wringing displayed by most modern bands is too easily proferred, but what's lacking is any sense of real engagement, at a time when war, terrorism and unemployment again vie for our attention. This, one supposes, is what has drawn Gang of Four back to the front-line. And not a moment too soon.

Not only do the band's anthems still ring true; because of their inherently cynical manner, they have acquired an even more bitter edge, the sour tang of prescience which accompanies such Cassandra-like prophecies. The social conditions which prevailed three decades ago are still essentially in place, which makes songs such as "Not Great Men", "At Home He's a Tourist" and "We Live As We Dream, Alone" as pertinent today as they ever were.

The latter, with its grinding riff, recalls a more agitated – not to mention funkier – Velvet Underground, a group whose influential status has been emulated by the Gang of Four themselves. A generation of American bands, most prominently the Red Hot Chili Peppers, has had its musical outlook transformed by the Gang's innovatory blending of muscular funk bass and drums, jagged guitar riffs and politicised lyrics.

But unlike the Velvets, the Gang clearly still manages to operate as a vital unit, as confirmed by the great rolling funk groove of new song "Hero", given pride of place following the mighty "Damaged Goods", the song which kick-started their career and which tonight prompts the loudest singalong. New bassist Thomas McNeice may be the most propulsive in the band's history, while new drummer Mark Heaney manages to sound like an entire percussive battery. And my namesake, I'm pleased to note, has become one of the great tectonic guitar sculptors of our age, his serrated tone and rhythmic slashes across the groove serving to detonate sonic bombs within the songs.

Onstage, Gill's stern manner makes an effective contrast to King's more effusive, animated presence; and he even endures with good grace a tiresome ongoing confusion with yours truly, when someone shouts out "Do you really love Coldplay, Andy?". For the record, I don't, and I've a feeling Andy Gill's probably not that keen, either.