Caroline Lucas: Forget the BNP. What about the planet?

There have been two big media stories of the 2009 elections: the demise of Labour and the rise of the BNP. Both were trailed heavily throughout the six weeks of the campaign. Both have received a good deal of attention since. But behind the headlines there's another story, a story that I would suggest offers Britain rather more hope than the other two: the rise of the Green Party.

In the European elections the Green Party increased its vote by 44 per cent compared with 2004. In both the South-east and the South- west, the Greens finished ahead of Labour. In Liverpool and Manchester the Greens finished ahead of the Conservatives. In the county elections fought on the same day, Green councillors broke through on to four more county councils. We won five more seats in Norfolk and another one in Lancashire. We out-polled all comers in Norwich and Oxford.

For the first time, the Greens are now within sight of winning seats at Westminster under first-past-the-post. Not many seats, but some. In the European elections we beat all the other parties across the three parliamentary constituencies of Brighton and Hove. In Brighton Pavilion, the seat I shall be contesting in the general election, we already hold a majority of the city council seats. I shall fight Brighton Pavilion to win.

We came first in Norwich in both the European and county elections. We hold a majority of seats in Norwich South, the seat to be contested by Green Party deputy leader Adrian Ramsay. Meanwhile, in Lewisham Deptford we came a close second to Labour. Lewisham Deptford will be contested for the Greens by Darren Johnson, the current chair of the London Assembly.

That we are on the brink of getting MPs into Westminster is good news, and not just for the Green Party. We are facing a triple crisis that the other parties still haven't quite got their heads round: the economic crisis, the climate crisis and the looming peak oil problem. According to a new report from a UN think tank, climate change is now reckoned to be killing 300,000 people, and damaging the world's economy to the tune of $125bn (£76bn), every year. So we urgently need to make prosperity sustainable in ecological terms. Who is going to do this?

Labour and the Conservatives are wedded to a neo-liberal ideology that insists market forces will solve problems that, for decades, market forces have demonstrably failed to address – not least the climate crisis. All around the world, people are calling for a Green New Deal. Gordon Brown gave us a so-called green stimulus package that on close inspection by the New Economics Foundation was only 0.6 per cent green. Far from selecting things that would create relatively large numbers of jobs quickly, like renewable energy and home insulation, Brown favoured things like nuclear and coal-fired power stations, which are not green and won't create jobs for many years, and even then will sustain far fewer jobs per megawatt than renewables would. This is what you get with a business-as-usual party.

Conversely, the Greens went into this year's elections with a manifesto calculated to create more than a million UK jobs within two to three years, while slashing CO2 emissions. For the Greens, it's never been about environment versus economics. It's always been about good economics, firmly rooted in social justice and sustainability, versus bad economics. The bad economics driven by the likes of Margaret Thatcher and Tony Blair, whose economic policies have wreaked havoc on Britain's public services, threatened our NHS, widened the gulf between rich and poor and neglected the sustainability imperative.

Can we expect a big Green vote in the coming general election? I would hope so, because the Greens have a lot to offer the British public. Who else would re-nationalise the railways and slash national rail fares? Who else would re-regulate the buses and provide far more of them? Which party is solidly committed to keeping the Royal Mail as a public service, publicly owned and publicly accountable? Which party has worked out how to pay for a £165 weekly basic pension? And which party is committed to ending the scandal of PFI hospitals, restoring free eye tests and dental care, and providing far better maternity services?

These are policies that command a great deal of support in the UK, so the challenge facing the Greens is mostly about getting our message across. The Green Party is notoriously under-reported, which is why so few people know about our policies for social and economic justice and so many still see us as mere environmentalists. But I do believe our million-jobs manifesto has struck a chord with a lot of the voters. As well as a massive increase in vote share, the Green Party increased its membership by 12 per cent in the six weeks of the 2009 election campaign.

There's talk of a big protest vote at the next general election. But I hope it will be far more than a protest. I hope it will be a positive vote for a new vision. We need to restore what decades of Thatcherism and Blairism have destroyed. We need to transcend the boom-bust model of economics, to proof ourselves against another credit crunch and to put the British economy on a truly sustainable footing.

We need sweeping electoral reform to make British democracy more representative of the diversity of British people and their opinions. We want politicians to care about people, and people to care about politics.

With British politics in a greater state of turmoil than at any time for decades, there has never been a greater need for change, nor a greater opportunity to bring it about.

Caroline Lucas MEP is leader of the Green Party