By Nick Assinder
Political Correspondent, BBC News website
It has become a cliché to claim the Green Party has got serious.
But even a short conversation with Caroline Lucas, the party's principal Speaker (nothing as traditional as a leader here - yet) underlines the truth of the statement.
Born:9 December 1960
Educated: University of Exeter, University of Kansas
Family: Married with two sons
Job: Principal speaker for Green Party, Member of European Parliament for SE England
Any suggestion this is a party of tree huggers determined to turn Britain in to some sort of village-dwelling agrarian state powered by windmills is quickly dispelled.
The Green Party is certainly about the environment - saving the planet even - but it is also about the NHS, women, pensions, transport and public services. Precisely the policies being fought over by the three big parties, she insists.
And there are, to coin a phrase, green shoots of support apparently sprouting across the country.
Dr Lucas is one of two Green members of the European parliament and the party has seven members in the Scottish parliament, two in the London assembly and over 60 in local councils.
It will field some 200 candidates in the general election and is hopeful of having its first MP elected - possibly in Brighton where it came first in the last Euro poll.
And targeting its slim resources for the maximum impact is what the party is all about in the looming campaign.
London Deptford, Norwich, Oxford and Leeds will all find themselves subjected to the attentions of the party as it attempts to make some sort of breakthrough in what many believe is a wide open campaign for the smaller parties.
"We have three key campaign themes we think will resonate with people," said Dr Lucas.
"One is around public services and our commitment to keep them public and challenge their privatisation which, to greater or lesser extent, all the other three parties are sanctioning or promoting.
"The second issue is around climate change. We have a prime minister who says its the biggest threat we face and yet is not only not doing anything to address is but is actually doing the wrong things.
"He has, for example, given the green light to road building and the greatest expansion of airport capacity for years.
"The third set of issues is around the Iraq war the issue of trust."
"Our difficulty is not having the policies, its getting the access to the air time."
And if they do get the opportunity, what is the vision the Green Party will hold out to voters.
"We are going to need to challenge the idea that acquiring more and more goods is the way to make ourselves happy.
"On the one hand it appears an arcane debate, but on the other hand it is an absolutely critical debate if we are seriously listening to the scientists who are telling us that we have a 10 year window to get ourselves in a position where we can seriously do something about climate change."
CPS:BOX TITLE="POLITICAL CV" IMAGEORDER="">
1986: Joined Green Party
1987-89: Green Party National Press Officer
1989-90: Green Party Co-Chair
1993-97: Green Party member of Oxfordshire County Council
1999: Elected Green Party Member of European Parliament for South East of England
2003: Green Party principal speaker
And it is on this central environmental issue that, unsurprisingly, Dr Lucas appears most passionate and most bitingly critical of the other parties - particularly Labour.
"To know the case, as Tony Blair clearly does, and yet not to do anything about it is something people in future generations will look back at and be completely aghast about."
There are elements of the Greens' policies which would undoubtedly hurt -60% tax on those earning over £100,000 a year and 50% for those on more than £50,000.
Air travel, private motoring, food are all areas that could see penalties imposed for non-green goods or activities.
"We need to put in place a policy framework that will make it easier for people to take individual actions that are the right ones," she says.
"You cannot tell people to leave cars at home without an affordable safe public transport system.
"There's no reason for organic food to be more expensive. The government could tax pesticides.
"And while making air travel more expensive, we should bring down the cost of train journeys."
It is an agenda Dr Lucas and the Green party believes is already taking hold in Britain and might just give them that dreamed of Westminster breakthrough.