First comes the trotting riff, then the beat, then the hum of distorted guitar - and then Malcolm Middleton gives the crowd what they came here for. "Woke up again today, realised I hate myself," he croons, his voice breaking around a delightful melody. "My face is a disease."

Middleton's output has been dominated by lyrical gloom. As one half of celebrated Falkirk duo Arab Strap, he has been responsible for countless scuzzy, booze-pickled laments. His solo sideline, which began with 2002's 5:14 Fluoxytine Seagull Alcohol John Nicotine, has hung similar sentiments on perkier rhythms: on his current album, Into the Woods, the music bounds about like a puppy while Middleton hangs his head in despair.

He doesn't seem too cheery tonight, either. When his eyes aren't shut, he is gazing at the floor like a sixth-form poet, or eyeing the ceiling apologetically. He breaks off at the end of songs to mouth obscenities. One senses he would rather be doing something less painful, such as rolling in broken glass.

Middleton has reason to be disgruntled: he and his band stumble occasionally, while the mix means that some lovely guitar shapes are crushed under muscular drumming. Still, you don't go to see a lo-fi hero for a flawless display. You go for fine songs, and Middleton has those in spades. Bear with Me begins with some choppy guitar work before a finding luminous vocal line. At the end of the gig, alone except for a fragile, folky guitar, Middleton laments: "I'm so lonely, I'm gonna get in a fight for the company."

Such dexterity means his gloom never seems too indulgent. Indeed, the impression throughout is that he has enough perfect pop hooks in his arsenal to launch the careers of a hundred chart poppets. Their loss is our gain: swathed in self-deprecation, swear words and a ramshackle playing style, the songs sound trenchant and gloriously sweet.

· Malcolm Middleton plays T in the Park, Kinross, on July 10. Box office: 0870 169 0100.