London's green goddess

Sian Berry, the Green Party's Mayoral candidate, is half an hour late for our meeting at the café in Highgate Wood. This is because, she explains apologetically, she took the bus from her home in Tufnell Park, and the bus was late. She does own a bike but - fair enough - she doesn't like turning up "all sweaty and horrible" for meetings. Like half of all Londoners, she does not own a car.

I, meanwhile, have driven an equal distance in my ancient VW Golf, and get to our rendezvous with enough time for a leisurely, pre-interview café latte.

Zero green points for me, then. Yet our respective journeys perfectly illustrate the problem Londoners confront every day. How is anyone going to persuade us to give up our cars completely when public transport is still such a hassle? How, for that matter, can Berry persuade us to live greener lives in general when "going green" seems so complicated, expensive and inconvenient all round?

Surprisingly, Berry seems to agree with my selfish analysis. "A lot of it is too complicated at the moment, and it just doesn't need to be. A lot of people are very confused about what can and can't be recycled, for example. I mean, I was too, up until recently. It was only when my boyfriend moved in with me and suddenly started putting all these weird things into the recycling box that I realised what I hadn't been doing."

I'm shocked. Like what? "Well, I didn't think Camden council would take those plastic punnet-things you get food in - I thought they only took plastic bottles, like for milk and shampoo - but it turns out you can recycle the punnets too." You need to look at the number on the side of the packaging, she says, which tells you what kind of plastic it is. "People just need clearer information. But that's what green policies are all about - making a green life easier, more attractive and cheaper for ordinary people."

Her boyfriend, Jim Killock, it should be said, is a member of the Green Party national executive, and its head of communications.

Of course, on 1 May, Berry will not wake up as London Mayor and begin to implement those policies. In the Standard's recent poll of influential London figures, she won just four per cent of first-round votes. But her presence on the campaign trail undoubtedly enlivens an otherwise all-male, though frankly allmaverick, battle for City Hall.

It has been noted before that 33-year-old Berry, formerly a Green Party Principal Speaker (the nearest thing it has to a party leader), is by far the most photogenic of the main four candidates. ("Pure environmental Viagra," swooned one male reporter.) But she is also the figure with whom ordinary young Londoners are most likely to identify. She lives in a flat above a shop - "I'd love my own little compost bin, but there's not even a balcony, so there's nowhere to put it" - and dismisses the eco-toff brigade (the likes of Zac Goldsmith and David de Rothschild) with a scorn bordering on contempt.

"[The eco-toffs] are giving green a bad image. It's this idea that being green is a bit of a luxury, something you do as an add-on to what is essentially a very wasteful lifestyle. The lowest income groups are actually the greenest, and they need to be told that and encouraged in it. Half of all people don't fly in a given year, and that obviously has a significant impact on a carbon footprint."

She is less willing to engage in electoral mud-slinging, and won't comment on allegations of cronyism within Mayor Ken Livingstone's administration. "I tend not to get involved in the bishbashbosh of politics," she says, a bit girlishly. But she does think the Greater London Assembly, which currently has two Green members (Darren Johnson and Jenny Jones) should have greater powers of scrutiny and be able itself to initiate policy.

She's quite a lot more fun on Conservative candidate Boris Johnson, however. "Boris doesn't do green. I'm sure at some point his campaign team will come up with something a bit environmental, because the Tories like to talk about it, but he'd probably reverse half the vaguely green things that have happened under Livingstone. Yes, he rides a bike. But it was the Greens who pushed through a tripling in London's cycling budget, and I bet Boris wants to divert that money into something else."

Berry studied engineering at Oxford University, and describes herself as a "very practical" green. Central to the Green Mayoral manifesto, for example, is a commitment to offer free insulation to every householder in London, with funding from the London Development Agency (the body occasionally referred to as Ken's "Piggy Bank") and the energy companies themselves. "At the current rate, it's going to take 100 years to insulate properly every house in London. I want it done much, much more quickly."

A Green Mayor, she says, would cancel the Thames Gateway Bridge, the £450 million proposed thoroughfare connecting the A406 at Beckton with Thamesmead on the south of the river. "I don't think building any more roads is a good idea. There's a lot you can do to ease congestion on other bridges, and with that amount of money poured into sustainable travel throughout the city, well, I could cure any traffic jam."

And so we are onto cars. It was Berry who in 2004 launched the Alliance Against Urban 4x4s, the campaign group that slaps fake yellow-and-black parking tickets - in fact leaflets containing information on CO2 emissions - on offending vehicles throughout London. I ask her whether she has ever met her arch-nemesis on this issue, Jeremy Clarkson: "No, but I'd love to. I'd love to debate it with him. Greens are not airy- fairy hippies anymore. They're cool people, committed people. They're businesslike."

So yes, of course she would raise the Congestion-charge to £25 for cars in Band G (the highest CO2-emitting vehicles) and, for a year at least, charge a zero rate to drivers of cars in the A and B bands.

"People do have choices. What I'm really concerned about is not how people's cars look but about safety issues and of course carbon emissions." As Mayor, she would also ban 4x4 adverts on the Underground, and is currently campaigning to have CO2 emission bands clearly printed on car adverts everywhere "like the tar content in cigarettes used to be".

But is she not simply anti-car? "No, I'm not," she protests vigorously. "I support people getting out of their cars but I'm not here to make life difficult for them. I want green to be enabling. If I make it more difficult for people to use their cars, I'd want first of all to make it easier for people to use public transport."

But how, how? The Tube is in a mess, the buses are often empty - or late. Berry argues for the effective " renationalisation" of the complete Underground network; says that she would put it under the control of TFL and insists that central government should cover the reported £500 million debt accrued as a result of Metronet's collapse last year. "The argument for PPP [Public Private Partnership] was that the private sector would run the Tube more efficiently. Well, they haven't. No one in London wanted it. It was forced through by Gordon Brown and now it's gone horribly wrong. We'd bring the Tube back under public control. Keeping fares low would be the absolute priority." She would also bring the timetables and fare system on some commuter overground train routes under TFL control - an undoubted crowd-pleaser. The daughter of two teachers, Berry grew up in Cheltenham and did not see her future in politics until she left university. "I've been a Green since I was very small, but then we all are I think. All kids grow up thinking the environment is important and that we must look after the planet. It's patently obvious really, but other priorities seem to get in the way as we get older.

"I grew up during the 1980s, with the first global warming scare and Chernobyl, when green issues started to become really important and the Green Party actually did best, electorally. But I wasn't political at that point. I think I assumed everything would be taken care of by the powers that then existed."

And while she waited for the politicians to wake up and wave a magic wand, she worked as a copywriter, and then a web designer for Imperial College. She joined the Green Party in 2001, and has never been a member of any other political group.

BERRY'S broad vision for London is certainly a little nebulous - she talks of " refashioning the city" by creating a "network of little villages", each one a miniature Utopia of independent shops and small, selfsustaining businesses, thereby removing the need to commute or drive to Tesco. She'd also like to reduce London's reliance on the City's muscle and " create a more resilient economy" across every borough - but doesn't really say how.

Though she won't admit it outright, she is clearly in the race purely to influence the other parties into greener policies. "You make the most difference when you're chasing their votes," she says. "That's when they get really scared. If you want to send a clear message, voting Green is the way to do it."

Yet her passion for greening the lifestyle of the ordinary Londoner - rather than the multi-millionaire pop star or the landed aristocrat - is undoubtedly refreshing. And however she fares over the next ferociously busy three months of campaigning, she'll be the only candidate for London Mayor to do it all by unreliable bus and sweaty Tube. Which is surely worth a sympathy vote or two.