Sian Berry, leader of the Greens

Sian Berry rolls her own cigarettes. She starts on one just as we’re leaving the health-food emporium where we’ve chatted for an hour or more. And perhaps because it takes so much longer to roll a cigarette than to smoke one ready-made, she still hasn’t finished it by the time we reach Bazaar’s offices. She looks for somewhere to drop it, then steps inside to choose from a selection of clothes selected for her to wear on our shoot.

Pushing the various garments aside, the most glamorous party leader in British politics, and one of our best known environmental campaigners, says flatly but cheerfully that she refuses to wear anything red. Why? “Because I’m a Green”. That said, she immediately afterwards declines a shirt in a particular shade of yellow: “It will make my hair look green,” she explains. There’s Green, it seems, and green.

Quietly, the PR officer accompanying Berry, conscious of the Green party’s reputation for frugality and abstemiousness, cautions her to stay away from anything resembling a hair shirt.

Berry continues to flick through, with barely suppressed excitement. But then she says: “I would not buy that white jacket!” Stepping forward with my notebook, I ask what ethical crime this particular garment represents. But it seems I’ve misunderstood. “Maintenance issues,” she says with a shrug. “White’s just not practical.”

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She chooses an item she’s happy with, made by Burberry, and steps away to try it. Meanwhile the PR calls Green HQ, only to be told that Burberry has used fur recently. And that wouldn’t go down well with party members. So Berry chooses something else, dresses, has her hair done and wanders with entourage towards Piccadilly Circus. A group of 10-year-old German girls, clocking the camera, ask for her autograph. “I did explain who I was,” she says afterwards with becoming modesty. “But they didn’t seem to mind.”

Berry, 32, was Green candidate for Hampstead and Highgate in the general election of 2005. She lost. Likewise, she missed being elected to Camden Council in both the 2002 and 2006 local elections – and daily places a curse on first-past-the-post electoral system. But in October, at the annual conference, she was elected to succeed Caroline Lucas MEP as the party’s female “principal speaker”.

The title requires some explanation: “In keeping with our radical roots,” says Berry, characteristically droll, “we eschew the traditional models of leadership, and the Shakespearean notion of concentrating power in one fragile individual. Instead we have a whole team of people who share the running of our affairs. Within the executive, we have two people – one man and one woman – who fulfil all the public functions that a ‘leader’ from the other parties might. These include speaking engagements, TV and radio appearances and so on – hence they are called our ‘principal speakers’.

Jenny Jones, a senior Green on the London Assembly, enthusiastically welcomes Berry’s appointment. “Sian is brilliant. She is competent and energetic, and passionate. She comes across as fresh and people warm to her. She has a great grasp on the policy and she puts across a side to the party that you don’t normally associate with us: she is attractive!”

Quite so. Berry has piercing blue eyes, and blond hair hanging low over her shoulders. She somehow contrives to look willowy even when slouching and stretching blearily over her coffee. And her personal appearance has had quite an effect: The Independent on Sunday described her as “pure environmental viagra” and a “Green goddess”. Followers of green politics, and possibly others too, will be excited to learn that Berry is currently single.

But lest this give a false impression, Berry doesn’t milk it. Arriving late to meet me, she looked ordinarily harassed and not the least bit pleased with herself – refreshingly unlike conventional politicians of either sex.

Blake Ludwig is a friend of Berry and a member of Greenpeace. He agrees with Jones that the Greens have chosen someone “incredibly dynamic and passionate”. But he goes further. He thinks Berry should be given a more powerful role. “The Greens have a thing against hierarchy. I agree that can be a problem in business, when the hierarchy is imposed. But if you find people who really are leaders, with passion and vision, I think they should be encouraged and respected. I think the Greens need a strong charismatic leader like the two main parties have.”

Berry was brought up in Cheltenham, where her parents were teachers. The oldest of three girls, she attended the local grammar. At Oxford, she studied materials science: many of her contemporaries went into the military industry, others into banking.

She wasn’t particularly political at college, she says – aside from organising a university-wide rent strike and going on the odd anti-Nazi demo. She voted Green in local elections but in the general election of 1997 she voted Labour. Some might argue that she would have more chance of effecting her policies if she joined Labour and changed it from within. She disagrees.

“Labour is a lost cause. It drives us mad that people think Brown might be any different to Blair – as believable as Cameron creating an entire new Tory Party with a flick of his fringe. (A survey of more than 10 000 people commissioned by the Green Party has shown Tory voters are the least likely to change their behaviour in any way to limit damage to the environment.)

After Oxford, she came to London. From 1999 to 2003, she worked as trainee copywriter, simplifying medical and pharmaceutical issues for nurses and GPs. Most of the work involved lucrative lifestyle drugs: “Drugs for obesity, and the Viagra family of drugs. I was working to get people to want to use them. I was pretty cynical about it.”

And she gradually became more political. “Look what happened during that period. The war in the Balkans, 9/11, the war in Afghanistan, and the build up to Iraq…” She started volunteering for the Green party, then joined up. “I got really excited trying to convert everybody.”

As she soon found, most people haven’t even heard of the Green party. Even those who have don’t always know that it has policies unrelated to the environment.

In power, the Greens would get rid of Britain’s nuclear, chemical and biological weapons. They would take the drug trade out of criminal control but regulate it, while banning advertising for alcohol and tobacco. They’d ban new out-of-town developments. Restore trade union rights and encourage cooperatives. Make the national curriculum voluntary. (“Education should be about developing human beings not economic units.”) And they would pay a “citizen’s income” to absolutely everybody, including children, to remove the dependency on benefits: with the income payable regardless of employment status, there’d be no point in doing nothing.

Berry spent a long time checking out the policies, she says, before joining the party. Then she resigned from her job and found a new one, at Imperial College, working on the medical faculty’s website. She was taken on full time and that’s where she works now, with a day off each week to devote to the Green party.

It was while travelling to work that she had the idea that made her name. “I was living in Highgate, and I used to stand every day at the bus stop during the school run. The streets were clogged with petrol-guzzling 4×4s. I thought, ‘Someone needs to do something about this.’ I went to find out who that someone was, but there was no one. I found that somebody in the US was doing something with leaflets on the cars. I thought I could do something similar. I was a copywriter, and I’d done some leaflets on giving up smoking, which is a similar problem, because people driving 4×4s know they are doing something wrong but don’t have the will power to give up.”

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She drew up a spoof parking ticket, a truly inspired work of satire designed to resemble the real thing but packed with information about climate catastrophe. She took it to her local Greenpeace group. “They said, great, we will use this. We had a whip round and got 1,000 printed up. The local paper found some and did a story. It was the start of a media frenzy. I was one of the journalists who wrote about the “Alliance Against Urban 4×4s”, as the group styled themselves. And I found the tickets so impressive that I sent off for some to put on the offending vehicles myself.

The media hoo-ha reached a peak as Berry took a holiday driving through Europe to Croatia. (“A lot of emissions, but not as much as flying.”) She spent most of the time on the phone to journalists. “It cost me a fortune.” When she got back, she went on Richard and Judy.

The actress Thandie Newton became a crusader against gas-guzzling cars after finding one of Berry’s stickers on her 4×4. Newton traded in the offending vehicle for a hybrid Toyota Prius, and wrote letters to other celebrities urging them to do the same. They included: Madonna and Guy Ritchie, Jamie Oliver, Chris Martin, Barry Manilow, Wayne Rooney, and the Hollywood stars Kevin Costner, Bill Murray, Meg Ryan, Jack Nicholson, Ben Affleck and Tom Cruise.

“There can’t be a Landcruiser or Cayenne driver in the country who hasn’t had their ear bent by a public-spirited friend over dinner. These factors do seem to be making the 4×4 unfashionable at last.”

It was the 4×4 campaign that won Berry her renown, and explains why the Green appointed her to her current position. But she’ll need to work a miracle to make the party mainstream. In the European elections the Greens won more than a million votes, but they still don’t have an MP at Westminster. If the next election is conducted under the current system, Berry concedes, they hope to win two seats in parliament, and move into second place in “at least” four others. Proportional representation is the party’s best hope. “With PR, people would be much more free to vote for what they believe in, so I’d expect 10 per cent support, if not more, and at least 40 MPs.”

Is a Green vote a wasted vote? “No. In places like Norwich and Brighton, our presence on the council is having a great effect. In Kirklees, they’ve managed to put up five per cent of the UK’s solar panels on their houses.”

In the meantime, while waiting to assume power, the party strives for its ends by lobbying government. In October, Berry travelled – by coach – to the Faslane naval base in Scotland to protest against the renewal of the Trident nuclear missile system. The UK is a signatory to the Nuclear Non-Proliferation Treaty, she says, under which we have promised to negotiate in good faith towards nuclear disarmament. “By keeping Trident and planning a replacement, the government is failing to do this.”

The campaigners, dressed in black, arranged themselves into the vague shape of a nuclear submarine in front of the base. “Weeks of work fiddling around with props, and planning worthy of the kind of military operation we’re totally opposed to, came off smoothly.”

At the same time, she must persuade the public – including people who will never vote Green – to change its habits.

Take aviation. How will she stop people flying abroad for hen weekends? “We can’t turn around to someone and say, I don’t want you to go. When it comes to changing behaviour, you have to be positive. Talk about how good this country is. Dorset is incredibly trendy, and Cornwall. We need to get our own tourist industry going. We have some great beaches. And I have really fond memories of camping in the Lakes…”

Not everybody, I fear, will be swayed by this.

While it’s important to convey the terrible urgency about climate change, she says, “You have to show what people can do about it. Imagine the Green party as the person in the disaster movie who says, ‘It’s OK, I used to work in this building, I know the way out. Come with me…’ We are really on top of climate change. This is something we’ve been thinking about for 30 years.”

There are some things we want to do that will cost money, but other things will save money. The government subsidises aviation to something like £9bn a year, and there’s no real economic benefit. We would also cancel road building. At the moment we’re spending £30bn on that. And Trident – that’s another £25bn.

According to Berry, the catastrophe facing us requires a five per cent cut in emissions every year. The Conservatives say they will achieve a lot with green taxes. “But they’re seeing it as a cash cow. You need to spend the money on ways to help the green measures easier to comply with. Gordon Brown put £45 on road tax for 4×4s but that’s not enough, it’s not going to change anybody’s behaviour.”

Just after this, we left the health-food shop and Berry started rolling up her cigarette. At the time, I hadn’t thought this a big deal – it’s none of my business if she smokes. But after talking to her friend Ludwig, the Greenpeace man, I wonder if it might be a problem after all. “I’m always on her case about smoking,” Ludwig told me. “She says she plans to give up and she knows it’s bad.”

I asked if he knew that she’d previously written guides to help people give up fags. He didn’t. Of course he didn’t. She didn’t mention those guides, because they plainly didn’t have any effect on her own smoking habit. So how can Berry hope to change other people’s behaviour if she can’t change her own? Forget aviation – how will she persuade people to buy ethical clothes, like the ones she wore on our shoot?

“I don’t want to be the green police,” she says, cheerfully commencing an answer that I correctly predict will end by urging me to vote Green. “My strategy is to look at the label. If something comes from a place where there might be a sweat-shop, I don’t buy it. If it comes from within the EU it’s probably good.

“People don’t have the time, when they’re buying a pair of socks, to find out how they were made. And I don’t want people to have to do all that research. I want the Green Party to help people make that happen at a higher level – by passing laws. We can make it unprofitable for manufacturers to do the wrong thing. So the solution to consumers’ ethical concerns is to vote for us.”