It’s not every day you see the former London mayor dancing on stage at a south London superclub. But such was the bizarre situation I found myself in on Saturday, under the roving lights of Elephant and Castle’s Ministry of Sound, chewing over housing policy between throbbing bursts of drum and bass.

This was Bite the Ballot‘s Youth Vote London. The mayoral candidates were invited to tackle youth apathy and test their mettle on one of London’s grittier electoral frontiers, alongside graffiti artists and urban poets. And, in the case of Labour candidate Ken Livingstone, to briefly show that at 66 you can still strut your stuff.

It was a welcome change from his usual war dance with Boris Johnson. The Conservative incumbent, predictably, snubbed the event, much to the chagrin of audience and organisers alike: “Boris doesn’t care about young people!” came the exasperated cry of one event manager.

Cue the partisan sniping – Livingstone decried “a mayor that just doesn’t really care about the people at the bottom of the pile”, independent mayoral candidate Siobhan Benita said: “he’s frightened of this audience”, while Brian Paddick, the Liberal Democrat candidate, smiled wryly and told me his absence was “typical”.

Typical it may be; but it is also emblematic of one of the more cynical, and dangerous, trends of modern politics – to dismiss the youth vote.

Yes, we may vote less – a private poll by Survation has found that only 31% those aged 18-34 definitely plan on voting on 3 May, compared to 68% of those aged 55 and over. But for a generation facing anunemployment rate of nearly one in four, this level of disengagement is as bewildering as it is tragic. Young people looking ahead see years of austerity, diminished public services and a working life extended to 71. For modern youth, apathy is an expensive luxury. Yet if the impassioned crowds on Saturday show anything, it’s that young people aren’t as indifferent as many in older age groups assume.

Unfortunately, however, the current political cast fails spectacularly to capture the imaginations of London’s young people. Where is London’s Obama, its Mélenchon, its George Galloway, even? The national conversation is dominated by things the young struggle valiantly to give a toss about – an Olympics they don’t have tickets for; how many floors candidate A can make it in an elevator without bursting into expletives; how many aircraft carriers the country owes to candidate B’s tax contribution. We want to talk about tackling postcode violence, easing unemployment and understanding knife crime.

And while Johnson’s absence on Saturday provoked the indignant snorting of his rivals, maybe it wasn’t worth risking comprehensive humiliation. His administration does consult young people, but it doesn’t take a sociologist to see that the Boris brand rings hollow in job centres and deprived areas. Especially as his tribe cuts education maintenance allowance and youth services, and tells young Londoners they simply lack “energy and appetite”. But Johnson isn’t the only one jumping to easy conclusions – Livingstone told me young people didn’t vote because they underestimated their plight under the coalition.

Ignoring the vulnerable is as ethically unpalatable as it is electorally unsound. Older voters are worried about the prospects of their children and grandchildren. And when young people are spoken to, they respond – as anyone who saw Benita’s performance at Bite the Ballot would have to concede.

Benita has been touted as the “Borgen” candidate, but on Saturday she looked like the odds-on favourite. Her audience repeatedly broke into rapturous applause as she urged them to “scare the hell out of the establishment”. Almost unanimously, people leaving the event said the independent was most impressive: “She’s reached out,” poet Dean Atta approvingly told me.

Benita’s policies are tailored to young people – she has a youth manifesto, and will take a pay cut to fund a youth mayor – but it’s her passion and sincerity that really resonates. Her campaign is run by friends and volunteers – as she proudly told the crowd, “my PR machine is here. Her name’s Gisele”. Afterwards, she told me she blamed the candidates for disengagement: “None of them are talking about youth issues. They’re not giving young people in London a reason to go out and vote.”

With trust in the Liberal Democrats and mud-slinging Labour at a nadir, Benita’s setting a shining example. The longer Johnson and Livingstone spend bickering, the better the chances of another candidate stealing a march.

It’s central to democracy that where there are votes to be won, someone tries to win them. Young hearts are there for the taking, but to get them out voting, the candidates need to dance to a very different tune.