The words tumble out, punctuated by nervous giggles. Tamsin Omond, independent parliamentary candidate for Hampstead & Kilburn and mildly notorious climate change activist, drinks her cappuccino. She refers frequently to a notebook that clearly contains the campaign strategy for her one-woman party, The Commons.

She has a lot of things she wants to say, lots of ideas. She articulates some better than others. She is trying to explain what her candidacy brings to the election. “I want to go in there and be a different vision of what an MP is,” she says. “If people are drawn to that and feel it delivers stuff for them in their area that’s great. If it doesn’t work, then we’ve got to keep thinking about different ways to get people involved in politics.”

The notion that what she’s trying might not work crops up regularly. She uses the term “social experiment” several times. It makes it sound slightly sinister. Naturally she’d like the social experiment to become a political movement, but that depends on how many people get involved. Her campaign proper starts next week, when the doors of her office on Finchley Road open to the public.

Right now, there’s a sense that this is work-in-progress. Some ideas are fleshed out – expect to see lots of activity in the streets, stalls, vocal campaigning. Others need refinement. This is a campaign light on policy but big on promise. “Obviously we can’t come in with six weeks to go and say ‘we’ve got the answers to your transport issues’. What we can do is show that we’re engaging with the issues that matter to the constituency and get them involved in coming up with the answers.”

There’s a sense too that Tamsin’s political career (although she avows she is not a career politician) is a work in progress. She’s not slick. She says things she probably shouldn’t. She tries to be refreshingly honest and upfront about her lack of experience and naïveté, although is swift to point out that these allow her to come at problems from a fresh angle. That she wants to effect change is clear. What is less clear is how that might play out in practice. Her ideas revolve around consultation, participatory democracy, doing what the constituents want. All very laudable but horrendously time consuming. Especially as she’s planning to spend one day a week doing community service.

Perhaps the idea with the greatest resonance is participatory budgeting. Giving the community control over a large part of the local budget can be successful. She cites Brazilian city Porto Alegre, where the notion has grown and taken hold. Implementing it here would be challenging, but such ideas have to start somewhere.

She’s fuzzy though about how exactly these forms of participatory democracy could work. It seems to be a combination of online voting based around a “What’s Tamsin doing this week” blog, and garnering opinions through meetings. Would such meetings be well-attended? Would it be the few or the many participating in Tamsin’s vision of democracy? “No-one’s ever tried to open things up before,” she argues. “So many people are so disengaged with politics and don’t see anyone doing anything for them. If you can change that, and if you’re a champion of that change, and if you’re really fun then people can get engaged.”

The fact that Tamsin believes she is fun and “energetic” and “charismatic” seems important to her. Certainly it will help her engage the dissatisfied and the disenfranchised. But are the people of Hampstead & Kilburn ready for an MP who is fun? Or do they want an MP who can be taken seriously in Westminster, who can cooperate with the two boroughs that the constituency straddles, who can focus on the boring detail as well as have imaginative ways to raise awareness.

“It would be naïve to suggest that by voting for me you’re not voting for something different,” says Tamsin. She is at her most incisive when it comes to the question of why she’s going it alone and the problems of party politics. “I don’t want to slot into the groups that are dealing with the realities they’ve been dealing with for the last 10 years. I want to do somethng very new and if it works then brilliant.”

“It’s very different going to Westminster to be whipped by your constituents than to be whipped by your party.” It’s her best soundbite. “So, a vote for me is voting for a different kind of politics, but it’s got to be something that’s credible and can be realised.” Addressing the credibility issue may be her biggest challenge.

There has been debate around how her candidacy may split the left/green vote in the constituency making it easier for Tory Chris Philp to take the seat. “I do think politics should be about choice,” she says, although it’s clear that Chris would be her least-favoured option as an alternative winner. Tamsin argues that LibDem voters are not going to vote for her because their candidate Ed Fordham has a real chance of winning and they’re not going to jeopardize that. “The people who were going to vote Labour or Green are in the same box as the people who don’t vote. There isn’t much positive to vote for with Glenda, and with the Greens – I haven’t met this woman [she never once refers to Beatrix Campbell by name], but she’s essentially a paper candidate. When she does go to hustings she’s really smart, but she doesn’t do any day-to-day campaigning.”

Strong words from someone who also seems keen not to antagonise the Green Party. There were apparently informal discussions with Green MEP and party leader Caroline Lucas over the possibility of Tamsin running in Holborn & St Pancras on the Green ticket. But Tamsin argues that she wouldn’t be able to criticise the party political system from within it, and nor would it have been easy to change the Green Party. She also points out that the Greens are focusing all their energy on the four seats they have a chance of winning, and Hampstead & Kilburn is not one of them. “So, all this “I’m stealing the green vote’ here isn’t true.”

Ultimately, Tamsin recognises that her core base of voters are the young and the disaffected – those who have never voted before. “Our campaign and the six-week window is going to seem quite lightweight to the people who vote and always vote. We’re not going to appeal much to those 45 percent of people who are already politically engaged.” But she thinks there are 25,000 people under 30 who didn’t vote in the last election. If she can get all of them she’ll win. It’s a very big if.