Not that long ago 26-year-old Jack Lukeman was an apprentice motor mechanic who would bounce his considerable voice off the walls of his boss's garage, an impromptu rehearsal room in County Kildare. Now he is a genuine pop phenomenon, just about to play three consecutive sell-outs at Dublin's Point Stadium. He needs only to cough to fill auditoria across the Republic and, seemingly, New York and Paris.

But Lukeman is little known in Britain: he made his Scottish debut at the quietest gig of the buzzing Big Big Country Festival. Seventy people (at a push) on Glasgow's permanently docked Renfrew Ferry is not a stadium crowd, yet the four-piece band, behind a battery of guitars and keyboards, played a huge, florid introduction as Lukeman made his dramatic entrance wearing thin sunglasses, even thinner trademark goatee and a frock-coat.

Everything about this melodramatic show was big. Lukeman is obviously used to massive crowds and immediate singalongs, so his stagecraft seemed slightly preposterous in the circumstances, as if U2 had played a Clydeside pub in full stadium mode.

The opening Georgie Boy, co-written with guitarist David Constantine, was characteristic of Lukeman's high-flown songs, treading the Bohemian path of Jacques Brel and Scott Walker and filled with romance and yearning. Lukeman looks almost human when he takes off his coat and shades and calms down enough to sing rather than strut. And he does have a phenomenal voice, close to Scott Walker's in its tone, control and huge range.

If only the show were less overwrought. My advice? Crank down the presentation, sit on a stool now and again and let the fabulous voice work for itself.