The mostly uncategorisable but approximately jazz-angled Dutch collective ICP (it stands for Instant Composers Pool) celebrate their 50th anniversary this year and the 75th birthday of their wonderful drummer Han Bennink. Less auspiciously, this year also saw the death of their presiding guru, the pianist and composer Misha Mengelberg. Yet the group still genre-hop with the insouciant agility of youth, as a 10-piece ICP proved with a vivacious set at Dalston’s Vortex Jazz Club.

Opening in typical style, they began on a lurching clamour of indignant-sounding reeds and brass squirts roughly resolving in stagily spooky Frankenstein chords. In came Mary Oliver’s violin drone and Bennink’s gathering drums, which shuffled into a folksy swing groove occasionally sniped at by trombone blasts. An agile free-jazz overture by trombonist Wolter Wierbos was accompanied by contrastingly impassive formality from Guus Janssen on piano, while jazzy walking-bass from Ernst Glerum strolled alongside slithery strings lines from Oliver and cellist Tristan Honsinger, and zestfully brittle violin improv ducked and weaved through sidling sax hooks.

A jaunty clarinet theme became a simmering tango jolted by Bennink’s hustling accents, and a dedication to German piano legend Alex von Schlippenbach fused a strutting march, a Bennink break of clattering hipness, as well as dissonant but ecstatically swelling long-tone harmonies from the reeds and Thomas Heberer’s trumpet, and eventually a coolly Ellingtonian orchestral glide.

ICP have always made their own rules, and hearing them followed, broken and reinvented in real time remains one of contemporary music’s enduring delights.

• At Gateshead International Jazz festival, 1 and 2 April. Box office: 0191-443 4661.