Have Greens finally found right conditions in which to grow?

As its conference annual conference opens, Andy McSmith finds a party ready to make an impact

Green Party members are on their very best behaviour. In just a few months time, when the next general election is held, they hope they will have their first elected MP. But first they must get throughtheir party conference without doing anything stupid.

If the evidence from council and European elections is to be believed, they are almost home and dry in the Brighton Pavilion constituency, where the sitting Labour MP, David Lepper, is retiring. Of the candidates lining up to take his place, the best known is Caroline Lucas, the Green MEP for South-East England.

The Greens took 31 per cent of the vote in the constituency in the last council elections in 2007. They have since won two council by-elections, increasing their vote, and in last year's European elections their support rose to 38 per cent, compared with 31 for the Conservatives and 22 for Labour.

So long as the Green Party stays in the public eye locally and does not implode, Brighton Pavilion should be theirs for the taking, and Lucas will enter the Commons as Britain's first Green MP. They also have outside chances in two other seats – Norwich South, and Deptford, in south London.

But those with long political memories will recall what happened last time the Green Party was close to breaking into national politics in a big way. It was 20 years ago, when support for the Liberal Democrats disintegrated because of a feud with the rival centre party led by David Owen, leaving a big hole that the Green Party almost filled.

As they assembled for their autumn conference in September 1989, they were at 15 per cent in the opinion polls, and had the committed backing of a national newspaper, the now defunct Today. But their conference turned into such a display of chaos and indiscipline that their position in the polls vanished as fast as it had risen.

One problem was their refusal to elect a party leader, fearing they would lose the happy, democratic chaos of a party full of people who liked being on protest or setting up peace camps. But today's Green Party is for grown-ups. Membership has swollen to about 10,000 – far fewer than in the main political parties, but also proportionally more active. They have a bureaucracy, including press officers who have learnt to be suspicious of journalists, and officials who can be overheard ordering taxis rather than bicycles.

There are even disciplinary tribunals, which on rare occasions have expelled party members. Owen Clarke, co- ordinator of the disputes committee, about the need for self-discipline, said: "There will be many stresses and strains as we work to obtain good Parliamentary representation. We cannot afford to add the extra strain of exaggerated internal disputes."

And after years of agonising, the Greens finally decided last year that they should have a leader, like any other party. Lucas was elected in September, though there is no prospect of her staying in post for years on end, like Tony Blair or David Cameron, without a challenge. After two years, she will have to reapply for her job, and she says she expects someone will run against her.

Now 49, she was working as a £5,000-a-year press officer for the Green Party when it blew its previous big chance.

"It was an emotional time to be a press officer, to see the party grow from almost nothing to 15 per cent and then see it go wrong," she said. "The party has learnt now to prepare for success. That means being disciplined about what you say, which is the thing with any political party."

Question time: So why are you a Green Party member?

Mo Jiwa, 25

I've been quite concerned about the state of UK politics, both on a local and national level, and I could not find anything in the other parties. The Greens, however, were principled and seemed to fit my own ideas of the world.

Sue Mallender

I've been a member since 1983. I joined after I read a leaflet in the general election around that time. I was overjoyed to find that I was not the only one with my viewpoint.

Nick Clinch, 19

They're more progressive. They're interested in the environment. They're out there to make a difference in the world. I hope to raise awareness about environmental issues.