Considering how long it’s been since NECROPHAGIA  last hit the UK, not to mention their roots in the earliest days of death metal, you’d expect a bigger showing than the one they get tonight. Frontman Killjoy isn’t fazed, though, brandishing a severed head and leading his recently rejigged band through the endorphin-releasing likes of Dead Skin Slave’s sputtering riffs, Chainsaw Lust’s past-scouring cacophony and the nursery-rhyme stomp of Whiteworm Cathedral. They may lack musical ambition, but Killjoy’s gleeful indulgence of his obsessions is infectious, and what crowd he has is at his command. The venue’s filled up considerably by the time VOIVOD  appear. This is not a band with casual fans; like a Magic Eye print, the Canadians have always necessitated a shift of mental focus, but once it clicks an entire new world opens up. Ramping up thrash dystopia into a visionary cyclone, the off-kilter, sonic brinkmanship of songs like tonight’s opener Killing Technology careers through its future-shock scenario like a crazed robot, frontman Snake’s punky snarl and ragdoll mannerisms a spur-of-the-moment narrative while the band frantically rifle through riffs around him as though searching for a working zap gun amid the rubble. Newer track Post Society is pounced on as much as frayed-nerve classics such as Korgüll The Exterminator – for the initiated this is metal nirvana.