It’s a full house when Portico Quartet take to the stage at the Black Box – perhaps surprising, since their music is almost calculated not to be to everyone’s taste. The appearance is their first gig of the new year for the Mercury-nominated English act, and the starting point for a pretty heroic 35-date tour of Europe. Although described a modern jazz band, their own website bills them as “like nothing you ever heard before”. That’s a challenging boast. But, as the first notes waft over the silent, 180-strong crowd, it is clear they are doing their best to live up to their PR. With a double bass, saxophone, drums and the eerie instrument called a ‘hang’, their sound is basically unclassifiable – a bit like Fingathing or Aphex Twin one minute, Björk or Thom Yorke the next, but never really that much like any of them (perhaps tellingly, there is no support on the night).

Without vocals or traditional structures, their songs resemble a series of rolling landscapes. If that sounds ostentatious, it’s because they occasionally are. Erratic rhythms, ghostly chimes and heaving swells of ambient noise – nothing so plebeian as a straight melody or a chorus to be heard all night. As this reviewer’s sister put it: “It sounds like being in the womb!” At one point they thank the audience for being ‘attentive’, a word which probably belongs more in a classroom than an entertainment venue. As if to hammer this home, they end their set with ‘Dawn Patrol’, complete with atonal sax solo – the poor instrument yelping and squawking for two minutes as if being devoured by pigs. It wouldn’t have been surprising if the Jazz Club presenter from The Fast Show had appeared and said: “Hmm… nice!”.

Perhaps it is unfair to criticise their intrepid oddness. After all, confronting musical boundaries is what they’re all about, and the world does not need another plodding indie band. Their musicianship really cannot be faulted, while their performance is often compelling, and occasionally breathtaking – as on the stunning new track ‘Lacker Boo’.  And they do manage to respect one musical convention: when the audience demand an encore. It is refreshing to see an act so defiantly gouging out their own niche. Just a bit more toe-tapping and less chin-stroking might be no bad thing. Adam Kula