In an evening packed with pinch-yourself moments, the first came walking through the audience. Eager teenagers mixed with beer-bellied rock fans in their forties, and trendy fashion types nestled next to suits straight from work. It would be easier to tell you who Jamie T doesn’t appeal to than isolate those he does.

That a scruffy 21-year-old who releases his debut album today, but is yet to have a big hit, could command such a crowd was odd enough. That a large proportion sang along to intricately observed urban tales, typically delivered at breakneck speed and in a South London drawl that makes Lily Allen sound positively posh, was remarkable. But then there is little that isn’t remarkable about Jamie Treays.

On his first tour with a full band — recent years have seen him playing pubs armed with only a bass guitar and, until fame came calling, he was the star of his own monthly Soho club night — Treays showed no hint of nerves but was a beanpole-shaped bundle of edgy energy. His legs constantly quivered through drainpipe jeans, his toes tapped in pointy, suede shoes and he stalked the stage as though for ever wondering where to head next, his face half hidden under a bobbing bush of black hair.

The music was as hard to pin down as the provenance of the audience, although Billy Bragg-meets-Beck summed up at least some of it. Like the latter, Treays pinches liberally from old blues and folk, assembles his songs like hip-hop records and delivers his lines in a white boy’s sung-spoken version of rap. Like Bragg, he harbours a pent-up, politicised anger that recalls punk rock, and Britishness seeps from his pores. Like neither, his songs are scattered with ska and, occasionally, drum’n’bass beats.

The opener Brand New Bass Guitar was a silly story about teenage choices that was half-rap, half-rockabilly. The current single, Calm Down Dearest, crammed more catchphrases than Little Britain into a loping pop rant about gruesome girlfriends. And the explosive highlight, Northern Line, sent an irate Clash anthem to a Pogues party. Jamie T may be pop’s jack-of-all-trades, but he’s also a master of most of them. Pyramids Centre, Portsmouth, tomorrow; Nottingham Trent University, Wed; Exeter University, Thurs; Ansom Rooms, Bristol University, Fri

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