It's during another one of those between-song breaks when strings are re-tuned and pedal settings are altered that a lone voice cries out, "Play 'Collision'!" Robert Hampson allows himself a smile before replying, "We've already played it." It's an easy mistake to make given that Loop have elected to play two sets tonight and the half-time break sees a mass exodus of smokers pile out of the snug confines of Hackney's Netil House for a quick gasper or two. As the opening bars of 'Collision' usher in the second set, there are enough collisions going on at the front door as the faithful squeeze back into the venue with all the grace of toothpaste being forced back into a tube.

It's one of the few changes that are apparent at Loop's first gig in 23 years. The lack of indoor smoking means that the fug of marijuana that once hung heavy during their sets is a long and distant memory while Loop themselves are nowhere near as hirsute as once they were. Robert Hampson now sports a silver mod cut while the rest of the band – guitarist Scott Dowson, bassist Neil Mackay and drummer John Wills - are clearly regular customers at their local barbers. But the music – oh, the music – firmly remains in the outer reaches of the stratosphere as hips, mind and soul are transported well beyond the confines of the here and now.

What becomes immediately apparent as Loop settles into its groove as the sound is balanced out during the opening triptych of 'Soundhead', 'The Nail Will Burn' and 'Fade Out' is how little the music has dated, if at all. Of course, there's much difficulty in resisting being mentally transported back to a time of late night chemical misbehaviour and deviant activities when Loop were the soundtrack of choice but right now, at a time when battle lines are being drawn in the sand in a far more brutal fashion than back in the 80s, Loop are just as pertinent.

Their timing is impeccable. With psychedelia enjoying something of a considerable resurgence and, in places, threatening to become the next bandwagon for hopeless chancers and pretty boys in polo necks and beads to hitch their nag to, Loop's re-emergence is a most welcome treat. Theirs is a reading that shakes off the shackles of the 60s and, in the process, creates something more timeless as it reaches across the decades with an ease bordering on the indecent. As evidenced by 'Afterglow', Loop has always eschewed the straight-ahead option to ram dissonance and discordance into the face of complacency and smugness. Similarly, the rolling drums and the punching and poking guitars of 'Arc-Lite' are propelled by urgency and an impatience that belies their cosmic image.

'Breathe Into Me' is where Loop truly hits its stride. With the sound mixed with all the care of a decent Old Fashioned, the brutal rhythm section allows Robert Hampson to take flight as the fingers of his left hand alternately throttle and massage the neck of his guitar while his booted right foot applies and eases pressure on his wah-wah pedal with equal measure. The effect is not unlike that moment when perceived reality becomes an altered state of consciousness. Crucially, Hampson's voice finds itself placed perfectly in the mix. If the opening numbers revealed his limitations as a vocalist in the conventional definition of the word, here it becomes another instrument as it hovers in and out of the guitars and drums to offer hints and haunts instead of certainties.

If, as has been written elsewhere, Loop have no plans to continue beyond 2014 then we're left safe in the knowledge that the short lifespan of their resurrection will burn bright and hard. Minor technical gremlins aside – Neil Mackay battles gamely with a stubborn amplifier – this is an assured performance that at once reminds us of what we've been missing and the frustration of not hearing what could have happened next. But as those last distorted and overdriven chords fade out into the ether, the realisation creeps in that none of that matters. The message is the same as it's always been – be here now. And we were and will be.