By day three of Flow, the ebb of the festival is apparent: it’s local heroes and off-beam curios early doors, rising acts and legends as the sun sets, and then the big guns to round off the night. The other dead cert is that anything on the extraordinary Balloon stage, a beautiful circular amphitheatre topped with a giant orb where bands play in the round, is going to be worth the time.

Horace Andy, six-decade dub reggae veteran and the only voice to appear on all of Massive Attack’s albums, is the only bone fide legend booked to play under the Balloon all weekend, and that combination of place and personnel proves irresistible: long queues form to get into the arena way before Andy’s stage time – a rare sight at such a carefree festival – and it remains one-in-one-out throughout his set.

And the discerning people of Flow are right to queue for this one: while much festival-programmed reggae can often feel a touch tokenistic or novelty – more background soundtrack to your late-afternoon bifter before heading off to see Generic Big-Box Festival Headliner #2 than musically expressive and moving in its own right – Andy’s booking here feels entirely authentic. After all, his huge back-catalogue and red-hot Dub Asante Band have form, pedigree and incredible chops, with perfectly timed chewing-gum bass and mournful trombone flanking Andy’s quivering, forlorn vocal throughout. His songs carry an emotional heft, too, the cliche of sun-kissed Jamaican hedonism rejected in favour of cautionary morality tales.

Reworkings of Massive Attack tunes pepper the set – ‘Man Next Door’ is returned to its origins as a first-wave ska track, ‘Five Man Army’ is full of slink and sorrow, and ‘Safe From Harm’ takes on a comfortingly consoling character when delivered by a gentle 72-year-old soul. But Andy is also no coattail-hanger: songs from his own Adrian Sherwood-produced most recent record have just as irresistible a lilt, and the classic ‘Skylarking’ lights up the darkening Nordic heavens just as the clouds start to roll in.

Indeed, so infectious is the Dub Asante Band’s groove that even audience members leaving the arena or climbing its stairs can’t help but do so with an off-beat skanking gait, and the result is a contagion of smiles across the packed arena, and the delivery of the perfect pick-me-up before Flow’s final-night finales get underway elsewhere. Between one pair of songs, Andy confesses to being afraid of flying; on this evidence, it seems a wonder that a singer with this level of float, poise, glide and hover doesn’t have actual wings of his own.