Despite that name, Of Monsters and Men aren't metal, though after experiencing their lusty racket, you perhaps wouldn't be surprised if a dragon or two turned up. This earthy Icelandic outfit specialise in fairytale-infused folk: jubilant, shoutalong songs about enchanted beasts, talking trees and transfigured kings. And these foot-stomping spells are demonstrably potent. They've already achieved uncanny success in the US, where their debut album, My Head Is an Animal, charted higher than fellow Icelanders Björk or Sigur Rós have ever managed.

It helps, of course, that they sing in English, and the fluency of singers Nanna Bryndís Hilmarsdóttir and Ragnar Þórhallsson is further tested when a drum pedal snaps in the opening minute of Dirty Paws. If it seems like a bad omen for such a thing to happen on the first night of a two-and-a-half month European tour, Hilmarsdóttir seems singularly unbothered, gabbing away breezily to the crowd. Sigur Rós have made a career out of being alien and remote, but Of Monsters and Men seem instinctively down-to-earth, from the mulchy references in their songs to their proto-Dexys wardrobe.

The rest of the gig is gremlin-free, although other sprites loiter in the margins of Your Bones – Tolkien imagery spliced with Motown drums – and Mountain Sound, which crafts a memorable chorus out of the very English-sounding line "Hold your horses now". Accordions and trumpets are passed around and pressed into the service of skiffle and shanty, but the real alchemy burns between Hilmarsdóttir and Þórhallsson.

Arcade Fire comparisons won't have hurt them in the US marketplace, but to UK ears, there's something of the open-hearted harmonies of the Magic Numbers, or even the last-breath vocal interplay of the xx. Both singers expertly wield acoustic guitars, but Þórhallsson is left-handed, so even visually they echo a magic mirror. It's bewitching stuff.