For all the improvisation it contains, David Thomas's live show doesn't change. He pads about the stage in bare feet, a child-size red apron comically perched on his voluminous belly, a tiny accordion that looks from a distance like a cartoon bomb strapped on top.

Each song follows a similar pattern: the Two Pale Boys, guitarist Keith Moliné and trumpeter Andy Diagram, weave a mysterious web of distorted melodies over which Thomas doesn't sing so much as spatter lyrics, the way Jackson Pollock threw paint at his canvases. Somewhere in the middle Thomas will begin to talk, punctuating his surreal narratives with swigs from a hip flask. And when he thinks a song is finished, he will put up his hands and the music will stop.

The familiarity of the form doesn't diminish the music's strangeness. It has an eerie, glittery quality: it could soundtrack almost any of David Lynch's films; equally, we could be listening to aliens in outer space. When Thomas remarks, "I'm an advance scout of an invasion from Mars," the notion doesn't seem far-fetched at all.

An uncanny telepathy exists between Thomas and Diagram, magnifying the evening's oddness. The trumpeter knows precisely how to capture his leader's "mood of desperation and waste". "Andy," Thomas instructs, "get us out somewhere warm - but not too warm. Somewhere comfortable - but not too comfortable . . . Somewhere where I can see the dust rising out of perfume."

And so Diagram begins to record his own trumpet, tilting and sculpting the samples to create a multilayered music, yearning and panicked in tone. It takes a while for Moliné to find his place in these angular melodies, but when the two men's playing locks together, it is exhilarating. They adapt to every vocal inflection, switching to a melting blues for Thomas's amusing love lament: "What will I do if you go? How soon can you go?"

For all their peculiarities, Thomas's songs and improvisations are strikingly beautiful. Man in the Dark shimmers and whooshes around his darting vocal. Later Moliné plays a lovely pastiche of the 1950s doo-wop song Duke of Earl, while Diagram sings into his trumpet's distorting microphone, creating an unearthly, incandescent sound. He could be a mermaid, calling across the sea. When Thomas pulls out his hip flask and offers Diagram a drink, it's clear he's impressed.