When the scrappy English jazz singer and pianist Jamie Cullum performs ''Blame It on My Youth,'' his age (only 24) and frisky personality lend the regretful ballad a desperate immediacy that a more mature interpreter could never evoke. Mr. Cullum, who made his memorable New York cabaret debut at the Oak Room of the Algonquin Hotel on Tuesday evening, is a natural showman with the confidence of a bantam rooster waking up the neighborhood with his crowing.
A fiercely swinging pianist, he attacks the instrument, daring himself to play almost faster and harder than his fingers will allow. When not pounding the keyboard, he often works up a head of steam by stamping his feet and drumming on the piano with his hands. And his rhythmically charged backup of drums (Sebaastian deKrom) and bass (Geoff Gascoyne) keeps kicking him into higher gear.
To watch a performer go so fearlessly on his nerve is exciting. And at the opening-night show the restless energy that poured out of Mr. Cullum recalled the younger Ewan McGregor in one of his bad-boy movie roles. It also evoked the early Harry Connick Jr., who conveyed the same ravenous enthusiasm when he burst out of the Oak Room a decade ago.
But Mr. Cullum, who cited Mr. Connick as a major influence (and sang ''It Had to Be You'' in tribute) lacks his forerunner's schooling in New Orleans jazz traditions. His attitude is more that of a bratty post-punk rocker dazzled by the potential of jazz to go anywhere and be anything. In addition to popular standards his set on Tuesday included songs by Jimi Hendrix (''The Wind Cries Mary'') and Radiohead (''High and Dry''), adroitly adapted into a pop-jazz idiom.
All this energy wouldn't count for that much were it not backed up by raw talent. Mr. Cullum reinvented ''I Could Have Danced All Night'' as a frantic jazz evocation of an all-night rave. When he relaxed to sing the Bob Dorough ballad ''But for Now,'' and his brother Ben Cullum's ''These Are the Days,'' he conveyed a throbbing, high-strung tenderness. Let's hope he doesn't follow Mr. Connick's example and spread himself too thin.