Mary Ann Sieghart: We need more independents to break the parties' stranglehold

Fed up with all three main parties? Fancy a bold, clever, sensible independent candidate to represent your city? That's what Londoners are being offered on Thursday, but the political and media establishments are doing their best to crush her. We have a 20th-century political system failing to cope with 21st-century politics.

This matters not just in the capital. Two other cities are voting for a mayor this week and 10 more are voting on whether or not to have one in the future. And we've seen all over the country that today's politics are tending towards to-hell-with-the-lot-of-them. In Bradford West, George Galloway won more votes than Labour, the Tories and the Liberal Democrats combined. In Scotland, the SNP won an absolute majority in a proportional-representation system that wasn't supposed ever to deliver such a thing. And national opinion polls show the fastest-growing support is for "others".

The introduction of city mayors was supposed to usher in more independent candidates. The idea was that we might have a Richard Branson or a Michael Bloomberg as Mayor of London. Hartlepool showed its distaste for the mainstream parties by electing a man in a monkey suit. But he was locally famous and Branson is nationally famous. If you are someone such as Siobhan Benita, the rules are seriously stacked against you.

Benita is one of seven candidates for London Mayor. She was a high-flying civil servant for 15 years and has more experience in government than either Boris Johnson or Ken Livingstone. She has no rich backers – the biggest donation she has taken is £3,000 – and has spent nothing on posters or advertisements. Yet despite that, she is third favourite to win on Thursday, and her odds have shortened from 500-1 to 33-1, putting her way ahead of the Liberal Democrat, Brian Paddick, and the Green, Jenny Jones. It's not surprising that Londoners are looking for a new contender when the three main parties have rolled out exactly the same tired candidates as last time round.

So why hasn't Benita been allowed to take part in any debates with Boris and Ken? This matters, because in a city of 5.8 million voters, airtime is by far the most effective way to be seen and heard. Every time Benita has had even a few seconds on television, visits to her website have soared. Yet, while Paddick and Jones have been on television debates and even the British National Party candidate has been allowed an election broadcast, Benita has been shut out.

The BBC's election guidelines say it should take into account past and current electoral support in determining how much coverage each candidate/party should have during the campaign, and whether they should be allowed an election broadcast. It interprets this guidance in a grossly unfair way.

Independent candidates such as Benita can't point to past electoral support if they haven't run before. Nor can they point to evidence of support for their party as they don't have one. As for current support, Benita is scoring just 3 per cent in the polls, but that's higher than Jones, who was given a place in the television debates, and higher than the BNP, which got an election broadcast. What's more, she argues, she would be doing a lot better in the polls if more voters knew of her existence.

Benita has offered other evidence of current support to the BBC. Her betting odds are far shorter than those of her smaller-party rivals, and even than the Liberal Democrat's. She has as many Twitter followers as Boris, and she has had more positive and fewer negative tweets than any other candidate. The BBC has told her that Twitter is new and untested – but so is the notion of independents standing for the London mayoralty. It's a pusillanimous argument.

For Benita is the future. Membership of a political party these days feels as quaint as membership of the Mothers' Union. We join Twitter, not the Tories, if we want to hang out with like-minded people. Over the past few decades, we've become much less tribal in our political allegiances, willing to judge each election on its merits. The logical conclusion of that, particularly when traditional politicians are so despised, is that we'll be ever more tempted to vote for "none of the above".

One way of doing that is to abstain. Another is to vote for a small party – and it's no coincidence that Ukip (whose London mayoral candidate has also been treated badly) is now nudging the Liberal Democrats for third place in national polls. A third is to vote for a genuine independent. This won't happen much in general elections. Party machines, however depleted they are these days, are still needed to campaign locally and run policy centrally. But in citywide mayoral elections, it should be much easier for candidates of no party to run and win – as long as the rules aren't designed to exclude them.

The London mayoralty already places quite high hurdles on potential candidates. They need 330 supporting signatures (10 from each of the boroughs), plus a £10,000 deposit and a further £10,000 in order to be included in the election leaflet that goes out to each voter. This process keeps the numbers down to a manageable level.

In some countries, all seven candidates would have to be treated equally. That's what's happened in the French presidential campaign. But if our broadcasters believe that seven is too many for a television or radio debate, surely they could include the two front-runners in each one and rotate the other candidates so they all have a chance?

There must be a better way, and we should demand it. If you live in London and are shocked by the unfairness of the system, you have a chance to say so on Thursday. Give your first preference vote to Siobhan Benita and your second to Boris, Ken, Brian, Jenny or whoever, and you will double your influence.

You will be able to vote for the candidate of your choice (as, barring miracles, Benita will be knocked out and her votes redistributed). But you will also be able to send a sharp message to the political and media barons that you cherish the idea of independents and you are determined that they should be given a fair run.