Sian Berry: The Green goddess and the would-be-goods

The Green Party's new leader is described as 'pure environmental Viagra', but can Sian Berry stop the main parties stealing her thunder? She talks to Tom Anderson and Geoffrey Lean

Blonde, blue-eyed and beautiful, she is the new face of British Green politics. But when The Independent on Sunday caught up with Sian Berry she was puffing on a cigarette outside the back door of Hove town hall.

The 32-year-old web designer at Imperial College was yesterday elected unopposed as one of the Green Party's two "principal speakers" - the nearest thing it has to leaders - at the party's annual conference in the genteel seaside resort.

Radicalised by school geography lessons, she made her mark as the party's campaign manager, attacking 4x4 cars in London. She claims the credit for Ken Livingstone raising the congestion charge on them to £25. In the last general election, standing against Glenda Jackson in Hampstead and Highgate, she was one of the few Greens to keep her deposit.

As the youngest, and most photogenic, leader of a British political party (eat your heart out, Ming Campbell), the Oxford engineering graduate will demolish any lingering image of beards, lentils and hairshirts.

"Pure environmental Viagra," sighed one reporter fresh from meeting her. She says: "I think my long blond hair has undoubtedly helped me get noticed in the media. I suppose it helps." Then she recovers her political correctness. "We're not as concerned with image as other parties," she adds. "It's not something I think about much."

She will certainly ride a new wave, with environmental politics rising rapidly up the agenda, after David Cameron's espousal of them last year. But she is predictably dismissive of her rivals' aspirations.

"The other mainstream parties are late converts, trying to steal our clothes, but its just window-dressing," she says, richly mixing her metaphors. "They posture in a green way, but their policies don't have any real substance. David Cameron is particularly fraudulent; you can bet that any green policy he talks about in opposition will be dropped if he gets into power and there is serious conflict with big business. Labour has proved good intentions and soundbites can be junked after a party is in government. I don't imagine the Lib Dems would be any different."

But if we are talking about hypocrisy, how does she reconcile smoking with her anti-pollution campaigning? She does not. "I have no excuses. It's terrible for the environment and I can't justify it. I'm just a big idiot".

Her political cynicism is justified. Tony Blair's government came to power in 1997 pledging to put the environment "at the heart" of its programme. It started promisingly with ministers genuinely trying to introduce green transport, agricultural and environmental policies. But their drive soon ran into an immovable road block in Downing Street, manned by Tony Blair and unelected advisers. Even over climate change, where Mr Blair has won deserved praise for bringing the issue up the international agenda, attempts to cut Britain's carbon dioxide emissions ran into Blair block as well. Emissions have actually increased since 1997.

The Conservatives largely dismissed green policies and Charles Kennedy, during his leadership of the Lib Dems, showed little interest beyond lip service. But in the past year, there have been signs that things are changing. The catalyst was David Cameron's election as Tory leader. He made green issues a central part of his leadership campaign.

It has worked beyond anyone's expectations. He risked campaigning virtually solely on the environment in the local government elections ("Vote Blue, Go Green") and won big.

Opinion polls have long shown that his green profile makes people much more likely to vote Conservative, and - as our poll on page 2 today shows - nearly half of Britons suspend political cynicism sufficiently to agree that his environmental concern is "a deeply held conviction".

Now the Lib Dems, too, are putting pressure on Labour over the issue. Sir Menzies Campbell has won the endorsement of the public for his policy of bringing in green taxes. The IoS poll shows that 55 per cent would support "an increase in taxes on energy if it were offset by a cut in income tax". However, it found sharp age differences on the issue: among under-45s, the level of agreement was as high as 60 per cent, falling to 46 per cent among over-64s.

But air travel is revealed as the main sticking-point, with public opinion evenly split on whether "air travel should become more expensive to help slow climate change" - 48 per cent agreed, 49 per cent disagreed.

Before 1997 Gordon Brown promised to be the greenest Chancellor, and failed to deliver. Now, however, he is working to make a difference internationally and last week secured a $20bn fund, against US opposition, for clean energy projects in developing countries.Will any of it make a real difference? Indeed, Sian Berry may remember that Greens too have sold out in office; there is little to show for their spell in government in Germany and other European countries.

But this time there does seem to be something different in the air, a feeling that an increasingly anxious public is demanding change, and will not lightly forgive another betrayal.