Nizlopi, Borderline, London <!-- none onestar twostar fourstar fivestar -->

As Luke Concannon tells the audience, it has been a strange month for Nizlopi, the two-man outfit he fronts with his double-bass-playing pal John Parker. Taking the same trail blazed earlier this year by the Arctic Monkeys, the Leamington Spa duo, both aged 27, have found that streaming the video for their single "JCB Song" on a website has garnered widespread word-of-mouth praise and a fan-base loyal enough to give them the pre-Christmas No 1 spot.

Apart from delivering another blow to an increasingly fearful and clueless industry, the homemade independently produced record is the only obstacle to the X Factor juggernaut.

On the afternoon before tonight's show Parker and Concannon sat on the couch with Richard and Judy. The week before a TV interviewer asked Luke to send a message to Bush and Blair ("I said chill out and stop bombing people. I hope they broadcast that," he smirks).

Tonight, attempting to reassert business as usual, Luke and John commence without microphones or amplification stood on the floor of the venue. The audience surrounds them while a posse of female photographers capture the moment from the stage.

Audience participation turns out to be a major plank of a Nizlopi performance, with communal sing-alongs encouraged and an ad hoc audience choir invited onstage to add support on "Find Me". As with the closing "I Love You" (partly sung in Korean) the latter doesn't feature on the pair's Half These Songs Are About You debut album.

However the formula remains the same - Luke's earnest vocals bolstered by his partner's boisterous bass playing and alternatively sibilant and tongue-popping human beatbox backing. The missing link between coffee-bar folk and homemade hip-hop, Nizlopi are an endearingly simply though hardly world shattering combination.

The image of the plucky little fella rising above his situation, captured in "JCB Song", recurs as Luke introduces the song "Helen", written, he explains, for a waitress encountered on a hiking holiday. Concannon is never afraid to allow the inner child to hold sway. In bare feet, past-the-knee shorts and check shirt, he is open, unaffected and constantly smiling, his face darkening only when he introduces "JCB Song". "People have said this is a novelty song, well they can all shag off," he snarls.

A second-generation Anglo-Irish working-man blues (with its quote from Christy Moore's "Don't Forget Your Shovel'), played live its easy to hear why the song has proved so popular - even before he gets to the bit about eating up the bullies and the teachers.

Whether, come Sunday, the song can eat up Shayne from The X Factor is another matter. But with performances like this - an ebullient blend of naivety, charm and unabashed sentiment - Nizlopi are likely to continue having "a top laugh" long after their present elevation has ended.