A record 200 candidates, standing on a platform of "people, planet and peace", will contest the election for the Greens.
Launching its campaign yesterday by unveiling a series of billboards pulled by bicycles, the party insisted that it was on course to winning its first seat in Parliament.
It will concentrate its limited resources on Brighton Pavilion, being contested by Keith Taylor, one of its two principal speakers. Labour has a 9,643 majority in the constituency, but the Greens now have six councillors in the town and matched Labour's vote in Brighton in last year's European elections.
Other target seats include Lewisham Deptford, Norwich South and Leeds West.
Mr Taylor said: "Even one MP is going to make a lot of difference. We're talking for so many different people. Our voices may be small but they are loud - we can influence and direct the debate."
The party hopes to gain the backing of Labour supporters disillusioned with the Iraq war, which it strongly opposed, but it may be competing for those votes with Respect.
It is also calling for investment in public transport, a ban on GM foods and animal experiments, scrapping the nuclear deterrent and for adults to receive a "citizen's income". This is a non-means tested weekly payment which would replace benefits and tax allowances. The party argues that the payment would ensure that anyone taking paid work would be better off, because they would no longer fear losing their benefits.
The party says affordable housing is "a basic human need" and would introduce policies, including tax penalties, to discourage "speculative ownership". It would seek a "balanced mix" of housing tenures, such as shared ownership.
The Greens now have more than 60 local councillors. They helped to oust Labour from power on Oxford City Council last year and have significant pockets of support in Lancaster, Stroud and Sheffield as well as Brighton. They retained their two MEPs - Jean Lambert in London and Caroline Lucas in the South-east - with 6.25 per cent of the national vote in the European elections.
The Greens say they will do all their campaigning for the general election travelling on public transport or bicycle or on foot. They claim the use of aircraft by the main party leaders during the campaign will release 100 tons of carbon dioxide into the atmosphere. Mr Taylor said: "We don't know why, but the other parties have obviously decided there is no vote for saving the planet. They are choosing to ignore climate change as an election issue."
The Greens, who will launch their manifesto on Tuesday, argue that Labour, the Tories and the Liberal Democrats are "singing from the same song-sheet" on the environment. The party says climate change threatens to devastate the developing world and says aid should be used to export "the very best clean energy technology". It calls for a drive to invest in renewable energy, including wave, wind and solar power, to cut CO2 emissions.
A claim by Charles Kennedy yesterday that the Liberal Democrats were the "greenest and most environmental of the three main parties" was ridiculed by the Greens. They claimed that the Liberal Democrats had left the door open for the building of more airports in the South-east.
* Introduce basic allowance, a "citizen's income", for all.
* Raise pensions by up to a third.
* Install two million solar roof panels over five years.
* Create 200,000 jobs in renewable energy industry.
* Shift £30bn from road-building to public transport.
* Scrap testing in schools and set aside more time for play in primary schools.
* Encourage properly regulated use of alternative health treatments.
* End animal experiments, ban live imports of animals, oppose factory farming.
* Produce 30 per cent of food organically by 2012. Ban GM food.
* Stop Britain's involvement in the arms trade. Give up nuclear weapons.