Truly great bands make fine albums but sound even better playing live, and Lau are one of the most intriguing and adventurous live bands in Britain, with a style that mixes traditional influences with virtuoso musicianship, improvisational skills and a sense of the unexpected that's worthy of good jazz players. This was an important night for the trio: the launch of their new album, Race the Loser, and their first headlining appearance at Welcome to Lau-Land, a four-day festival featuring "musicians we like". It was perhaps to be expected that the finest song of the evening would be the least expected, and one that doesn't even appear on the new release. Midnight Feast is a cheerful, gently erotic song by the late Lal Waterson, which Lau recorded on an EP with Karine Polwart two years ago, and was used here to demonstrate the intuitive interplay between the band members, and their new fascination with electronica. It started in conventional style, with guitarist and singer Kris Drever matched against the fiddle playing of Aidan O'Rourke. Then Martin Green joined in, adding accordion and keyboard, before switching to a barrage of electronic effects and then returning to accordion for a furious workout. It was a remarkable exercise in musical dynamics, in which the three players eased between gentle passages and thrillingly loud and frantic sections in which it seemed that Green would fall off his stool in excitement. Earlier, they performed pieces from the new album, from the thoughtful and drifting Saint Monday, about industrial decline, to the sturdy The Bird That Winds the Spring to the sombre and then attacking Save the Bees. Lau in full flight were epic and exhilarating, and matched the Punch Brothers for the most exciting and original live performance I have seen this year.