The word on everyone's lips in Greece is "Potami". It is the name of a new party, or movement to be more accurate, created by the respected journalist Stavros Theodorakis barely two weeks ago and already polling around a staggering 6% in national surveys. It means "river" because its founder hopes that many will be able to join it, add their creative waters to its flow and that, like a river, it will stir up – but also bring clarity and vitality to – what he sees as the stagnant pool of established party politics.

I meet Stavros (he insists on everyone calling him by his first name) in the offices of his new party – a first-floor apartment in an inconspicuous block of flats in a residential part of Athens, converted to provide a working space. "Come in," he says, adding that "it's all suddenly got very busy." Well, yes, if you decide to start a party from scratch and put it in the hat for the European elections in two months' time, I imagine it would. "What do you want from me?" he asks with a friendly directness, which has become the trademark of his investigative television programme Protagonists over the years. "I'm not doing interviews yet." So we settle on this being a coffee and a chat instead.

How does he respond to the charge levelled by some that, despite good intentions and an admirable start, Potami doesn't have a coherent and sound ideological basis? "We don't," he agrees proudly. While it is clear that his sensibilities are centre-left, he considers rigid ideology a hindrance. "Everyone wears their party specs," he explains, "and sees the world with a red or blue or green tinge." He thinks this brings a lack of clarity, that such labels act to segregate politicians and make finding solutions to practical problems more difficult. "Even the way they sit in parliament is silly – in blocks of party MPs, all putting on a uniformly approving or disapproving expression depending on who is talking." He asks: "Why shouldn't I sit next to an opponent so we can discuss an issue and try to convince each other or a colleague from another party with whom we might have common ground?"

He considers a rigid party system a disadvantage, rigged to facilitate not listening to each other or the electorate. This is one of the reasons Potami is not putting forward any candidates for the municipal and regional elections that are also happening in May. "What do I know of local issues in, say, Crete, to try and impose an overall, national strategy?" So why start at the European elections? "It's cheap," he responds with a smile – there is that disarming honesty again. He is not standing in the European elections himself. Refreshingly (and rarely for a politician, even one as new to the game as he is), he doesn't consider himself qualified. His English is not good enough, he says.

Potami aims to be a movement that includes people from all walks of life – doctors, builders, architects, students, intellectuals, employed or unemployed. The credo at the core of its existence is to address the deficit of real-life experience in politics. We talk some more about the party system and his belief that it promotes a closed shop of career politicians. The right is laden by nepotism, dominated by particular families with respectable surnames, by privilege and by connection. The left has similar problems because it rewards people who have been loyal to the party (or the union) by promoting from within. In both cases, according to Theodorakis, the end result is that the candidates put forward have a CV packed with political experience but little else to recommend them. The motto at Potami is "politics for all".

Theodorakis is to be enthusiastically applauded. Whatever the political limitations – and perhaps lack of polish – of what he is doing, the bottom line is that he is doing it. In a world seemingly full of citizens who are either apathetic or see themselves as passive recipients of government policy, active ownership of one's fate and that of their nation should be encouraged. He will come under fire over the next few months without doubt. He represents a serious challenge to the status quo – and not only in a strictly Greek context.

Established parties in most mature democracies have become floppy and complacent. Their sole raison d'être is to be elected, with little idea of what that means or what they might achieve when in power. They define their policies strictly with reference to the direction in which they are in danger of losing votes, rather than the national interest or a core set of values. Imagine a pop-up party like this suddenly challenging the Ukip-obsessed Tories from the centre or Labour from the left. A measure of political unpredictability may act to keep politics honest.

Conspiracy theories are rife – in a country which is a bit of a specialist in the field – about who is behind Potami, who might be funding it, what interests it might represent. Political players and commentators alike seem prepared to countenance every possibility except one: that someone with broad appeal could just decide they are unhappy with what is on offer and do their own thing. And that it could be successful. In many ways, this simplest explanation is, politically, the most dangerously explosive and optimistic one.