Sian Berry was the Green Party’s London mayor candidate in 2008. I don’t recall her saying sentences like this: “The reason you need to build profit into your development plans is because of risk. But if you know you can get something through at a lower risk, you plan for a lower profit.” Or this: “I want to see total transparency on viability with a non-technical summary appraisal.” Or maybe this: “Landlords’ mortgage interest relief is not a business expense, it’s an investment expense.”



This is not to argue either that Berry was a hopeless innocent eight years ago or that she has since contracted wonkitis. Rather, my point is that she, like her party, has grown more formidable with experience. In 2008, Berry was known principally for throwing drawing pins (metaphorically, as far as I know) under the tyres of Chelsea Tractors. In the ensuing years she has been, as she puts it, “Learning how politicians and civil servants work.” As well as writing books she’s been in the thick of the Reheat Britain campaign to fund the government boiler scrappage scheme, worked for the charity Campaign for Better Transport and, in 2014, won a seat on Camden Council, which means she now immerses in the simple pleasures of community infrastructure levies and corporate performance scrutiny.



Like her outgoing colleagues on the 25-member London Assembly, Darren Johnson and Jenny Jones, Berry has therefore engaged profitably with the machinery of London government, helping the capital’s Greens to test their idealism against practicality and invest it with credibility. The party has increased its London membership and considers itself a more mature and hardened political fighting force.



But this does not guarantee that Greens will make advances in the forthcoming London elections. With both the Liberal Democrats, whom Greens tend to battle for the environmentalist vote, and Ukip taking larger vote shares at last year’s general election - around 8% for each compared with 5% - consolidation would be a good result. Berry is unlikely to win the mayoral race and will be pleased if she repeats Jones’s 2012 feat of finishing third.



Anything less than retaining two AMs will be a disappointment. Berry is running in that race as well, heading her party’s list of candidates seeking election through the proportional representation element of the Assembly electoral system that produces 11 of its members. Her fellow London councillor Caroline Russell, the sole voice of opposition in Labour-dominated Islington Town Hall, is vying to keep her company. Any advance on two AMs would be a major triumph. What is not in doubt is the ability of Berry, 41, to make her party’s case. She has performed well at mayoral hustings and in broadcast interviews so far, emphasising a distinctive Green approach to the bedrock issues of housing and transport and how these articulate a wider Green London agenda.



When we met at a cafe near where she lives in Kentish Town, she again articulated defining themes of her approach to providing homes that most Londoners can afford: diversification, conservation and community. “There’s a lot of things we want to do to influence the housing market and it’s not just build, build, build for supply, and it’s not just leave the market to itself,” she says. “I want to increase the number of ways we’re providing housing - a more diverse eco-system of options.”

This would embrace and encourage smaller developers, house-building co-ops and self-building: “Let a thousand flowers bloom.” She’d want Transport for London (TfL) to take a very different approach to its dozens of developable sites around the capital. It has recently announced a panel of big-time “developer partners” it will work with on the first 50 or so sites, retaining ownership of the land and forming joint venture companies to build it out. “I’d break those bigger sites up into smaller plots and look at all the smaller sites as well,” Berry says. “There’s too much concentration on the big developers.”

Speaking more generally, Berry argues that although the property giants have the capacity to build large numbers of homes at high speed, they tend to lack the inclination. “Big developers have an incentive to release things slowly on to the market and keep prices going up, so that they are more profitable. The non-profit making models I’d want to encourage would have none of that incentive to wait.” She’s been critical of Camden and King’s Cross developer Argent for negotiating a reduction in the number of affordable homes on the 67 acre site, both intermediate and for social rent. “We could be looking at King’s Cross after King’s Cross in London,” she says. “We’ve got to think creatively about how we do these things.”



She commends Darren Johnson’s report Where Can We Build More Homes? which looks at various ways of adding to housing stock that don’t entail environmental damage, large scale demolition or trampling over the wishes of local people. He argues for restricting the provision of car parking spaces, building extra floors of housing on top of existing buildings and putting residents in charge of regenerating estates. A Community Homes Unit in City Hall would dispense expertise. Berry was announced as her party’s candidate in a community hall on the West Kensington estate, which is threatened with demolition as part of the vast and controversial Earl’s Court redevelopment scheme. Campaigning residents want to take ownership of the estate and an adjoining one and put redevelopment decisions more firmly in the hands of residents, following the example of Walterton and Elgin Community Homes in Westminster.



“I want to preserve the housing estates we have so that we still have social housing, and I want to build more social housing too,” Berry says. She understands the case for knocking down and rebuilding estates in ways that increase the quantity and quality of housing on the site if this doesn’t result in a net loss of social homes. It does not, however, persuade her. “You’ve got the ten years of blight there are on such sites. The leaseholders, who are the very people the Conservatives had in mind when they invented right-to-buy, are unable to buy a new house in the area.”



Far better in her view to fix and in-fill and stick to brownfield sites that properly merit that name for building new stuff, including, with community blessing, market-priced homes that can subsidise “affordable” ones elsewhere. She isn’t taken with Lib Dem candidate Caroline Pidgeon’s idea of setting up a mayor-owned house-building company, believing that the numbers don’t add up. Berry says that she, like Pidgeon, would keep City Hall’s Olympic precept going and put the money into housing, but would also increase the mayor’s council tax take for the same purpose. “You can still put together a fund,” she says. “But the really important thing is to use that money in the best possible way. There’s a lot more you could bring in by striking deals with social landlords and small developers and a wider range of investors. I think in terms of delivery you get more homes more quickly in that way.”



The Greens have also proposed setting up a London Renters’ Union, supported by but independent of the mayor, to assist, resource and foster the further growth of grassroots private sector tenant campaign groups across the city with the aim of exposing bad landlords and letting agents that break the rules. Berry, herself a private renter, would also argue for the mayor to have rent control powers. She’s undeterred by academics and others who think that in the London context the drawbacks of such measures could outweigh the gains, doubting that a damaging loss of supply would result.

Berry’s frequent stress on “providing help and expertise to support people from the ground up” is also reflected in her enthusiasm about the potential of Neighbourhood Plans, a Tory “localist” initiative designed to devolve influence over planning matters to local people. There’s one brewing in Highgate, covering an area that lies partly in the Camden ward she represents and partly in Haringey, and another in nearby Dartmouth Park which falls entirely within her patch.



On transport, Berry has announced an ambitious plan to phase out fare zones and introduce a flat fare system within ten years. She says her “ONE ticket” idea, which would enable people to pay a single price for journeys to a defined destination irrespective of changes of mode along the way, is considered do-able by TfL and has been costed. She takes a critical view of Boris Johnson’s approach to managing London’s streets. “He’s doing predict-and-provide, essentially - looking at the growth in traffic we expect related to population. That’s why he’s planning to create more roadspace - new road crossings in the east of London, road expansion plans, road tunnels and so on. It’s really very poor that he hasn’t talked at all about reducing demand. That’s what we need to get to grips with, and there’s loads that we can do because so little has been done.”

A Mayor Berry would introduce a workplace parking levy - “it’s easy to administer and it’s worked a treat in Nottingham” - and a new system of congestion charging, which she says is being looked at for London without a word being breathed about it in public. Berry anticipates that if introduced this would affect a wider area than the current charging zone and have fees based much more on distances and time of day travelled than the present flat rates: “It would give people an incentive to travel outside of rush hours and be fairer too.” Tariffs would also vary according to how polluting a vehicle was, making it also “potentially a replacement for the [planned] ultra low emission zone, which is going to be inadequate. They went for something that was cheaper and easier instead of what was most effective.”

The Wild West atmosphere on many London streets is an issue for Berry too. “There is a battle going on for space on the roads at the moment. You have to prioritise the most efficient ways of getting people - not vehicles - around.” She wants to improve conditions for pedestrians and give more priority to cyclists, believing that segregated lanes “are the way to get everybody cycling, giving everybody the option to cycle from eight years old to 80.” She likes the principle of testing local road system changes on a temporary basis in order to see what does and doesn’t work and to lessen anxieties about change.



Then there’s public transport. “With new bridges across the Thames, we’ve got to be looking at public transport links before we look at new roads,” she says. She favours the Brunel Bridge proposed for pedestrians and cyclists that would connect Rotherhithe and Canary Wharf and would like another spanning the river on the other side of business district, connecting to the Greenwich Peninsula. Even a heavily-tolled road bridge would be “the last thing I’d do down there. It’s not an opportunity cost in terms of investment. I would like to cancel all the current plans for east London and look at the problem from scratch. If you’re developing the Thames Gateway area, you’ve got to think about where people want to go. They want to go into town. They don’t want to go from Kent to Essex across the Thames.”

Berry is as eager as ever to discourage car use in general. Responding to a Twitter question from @howarthm she thinks the opportunity is there for Central London to have no private cars on its roads except for those in car clubs and says she’d want “an expanding programme” of car-free Sundays. She’s hopeful that car-ownership and car use in London will continue to decline. “If you look at the reasons for people driving less, a lot of it is demographic. Younger people aren’t interested in owning cars to same extent as their parents were. It isn’t as much of a marker for success as it used to be. The car companies are on to this, so BMW’s big car-sharing push Drive Now, which has been happening in German cities for ages, has come to London. They want young people to see their cars as things they might want to use, but not own. It’s not like how it was with people of my age and over. You know: ‘When are you going to buy your first car?’”

Arts and culture haven’t had many mentions in the mayoral race so far. South Londoner tweeter @SamuelWilock sought Berry’s views, pointing out the social and economic benefits the creative industries bring. The Green candidate agrees: “It’s one of the best things about London, isn’t it?” She recounts a visit to the William Morris museum in Walthamstow to see an exhibition about arts education and its value. “The arts should be for everyone,” she says. “The trend that worries me is that the arts, culture and success in all kinds of creative fields is becoming more restricted to people with the financial means to support themselves.” She’d like to find ways to raise money and resources to help correct that. “It will be in our manifesto because it’s so important.”

Berry personifies the distinctive Green combination of big visions pursued through small initiatives. I’ve described her as the “small is beautiful” candidate, a reference to the influential 1973 book of that title by E. F. Schumacher subtitled “a study of economics as if people mattered.” She seems at ease with the comparison. “I think that’s right. We need more diversity, more small businesses, more things happening at a local level. I think that leads to better big outcomes in the end.” Her most ambitious policy announced so far, a plan to close London City Airport and redevelop it as a new kind of urban neighbourhood complete with homes and innovative small businesses, is a bold articulation of this philosophy.



What would a Green-led London be like? How can those rather restful Green values be squared with the London of permanent change and booming growth, the throbbing engine of the national economy? “I’m not particularly keen on the engine metaphors!” Berry laughs. What she does like is London’s “openness, inventiveness and excitement.” But she’d try to nurture “an economy that works for everybody, where everybody’s got more opportunities and is involved in running London, so it doesn’t feel like it’s out of their control. That is how a lot of people feel at the moment. They feel buffeted by the out-of-control forces of the housing market, they don’t feel in control of their own jobs, their own time. People need to feel more content about their place in London.”

It feels impolite to ask which rival candidate she think Green supporters should give their second preference mayoral vote to, but it would also be remiss not to. In any case, Berry prides herself as someone who can work constructively with an array of different people. The Greens are nowadays seen as a party of the left and Berry says she preferred Ken Livingstone’s approach to being mayor to that of his successor Johnson - Greens worked with Livingstone quite productively. When I ask her where she places herself on the spectrum of opinion on housing estates, which Tory Zac Goldsmith is eager to redevelop and Labour’s Sadiq Khan has pledged himself against demolishing except in “exceptional circumstances,” she jokes that she’d be on “the ultra-violet end, beyond Sadiq.”



And yet: “I’m not just a rabble rouser, I really believe in putting forward ideas that other people can take up, even if they are Conservative. Even if I’m not mayor I hope some of the ideas in our manifesto will become more mainstream.” There will be a London Green Party meeting next month to consider whether it should endorse another candidate for second preferences and, should the decision be yes, a second meeting in April to settle on which one it will to be.



For Berry, there are a couple of “red line” issues - road river crossings are one and any new airport runways is another - but the decision will be the party’s. Whatever path its members choose on that matter, a Green presence in City Hall would continue to broaden and enhance the institution’s deliberations and debates. “We are the party that looks into the future and comes up with a vision for how things could be,” Berry says. She has a point.

