Putting a bipolar singer-songwriter who writes harrowing songs about the human condition on at a comedy club seems like a bad joke. However, the clamour for Johnston's public exorcisms often misses his work's black humour. It is perhaps a way of coping with his illness, but there is little doubting the relish with which the Texan delivers knowing lines such as, "I'm nowhere to be seen. I'm out to lunch."

In fact, though his hefty belly suggests he certainly enjoys his dinners, the 45-year-old seems in better health than he's been for years and is visibly delighted at the crowd he has drawn. Taking applause like a child who has just received a gold star, he bashfully quips, "Are you still there?"

However, it's not long before Johnston is giving the audience what they crave - searing songs containing insights unlike anything else in pop. As perfect in construction as anything by the Beatles or Burt Bacharach, it is difficult not to shift uncomfortably at quivering lines like, "Would you follow me anywhere? Are you entertained by deep despair?"

And yet, Johnston is a terrific entertainer. No longer performing two songs and then trying to flee through a window, he plays for an exhaustive 75 minutes and delivers all his "greatest hits" - from a wonderfully childlike Walking the Cow to an astonishing rendition of Go, as covered by the Flaming Lips. There is more comedy as he starts a different song to his guitarist, who sighs warmly at his employer, like a long-suffering parent. Johnston seems equally blissful singing about washing his underwear or unleashing songs of desperate hope like True Love Will Find You in the End. The screams for more are deafening, so he briefly walks back on a fourth time, then decides against it.