Katy B, Koko, London

Koko is bursting at the seams, limbs hanging over balconies, enthusiastic fans crammed in at the front needing water from security, gasping before an empty stage. The phrase "sardines in a can" comes to mind and the electric excitement brewing is almost killed by the late starting of the show, but all is forgiven as the Peckham star bounds on to the stage.

It's very hard to pinpoint the sound, not in terms of volume (which was certainly in abundance,) but genre-wise; you can't box this girl into any category. Each track draws on a rich variety of influences, from UK garage, R'n'B, jazz, and even a bit of Latino salsa thrown in with dirty bass lines and the odd dose of killer dubstep. It's a delicious assortment of chocolates where each bite brings a new and interesting flavour.

The six-piece band adds a particular zest to the set, the vital ingredient being the brass instruments. The trumpet and saxophone create an edge on every track, creating an almost lounge-like atmosphere between songs, the singer flirting with the crowd with an easy charm. In a shiny tracksuit top and big gold hoops, it's not so much "chav" as confidence: Katy B dresses up for no one. Jumping around to the music she makes and loves in black jeans and plimsolls, she is as much a part of the crowd as she is the performance, and this duality is certainly a key to her recent success.

"Katy on a Mission" and "Lights On" are definite crowd-pleasers in line with the current hunger for dance music, something that Katy understands and translates to the crowd. "You know when you in a club, and you look at the person next to you, you don't know them but the music brings you all to the same level?"

"Katy on a Mission" in particular has the crowd jumping in a frenzy, although the hard bassline doesn't translate quite as intensely live; the brass instruments overpowering the dubstep feel. Interestingly, it rose independently to number five in the charts and this sums up Katy B: the music speaks for itself.

The young crowd hangs on every word and note; the singer's range is impressive to say the least, hitting high notes with ease, dancing over octaves and toying with the melody.

Red searchlights sweep from the stage out to the chanting crowd as they ask for "one more song" but eventually "the lights must come on", and the energy spills out onto the Camden streets.