The leader of the Green Party has said the organisation can be the alternative party of government.

Caroline Lucas said the Greens could become "the radical and credible alternative" to Labour.

"On Iraq, we have the choice between two parties of bomb and kill, and a third party of reluctant bomb and kill," she said.

"On public services, there's a choice of three parties of privatisation. On globalisation, three parties entirely committed to neo-liberal free trade."

Turning to her party's central message - the environment - Lucas claimed the three parties "all completely fail to understand the absolute revolution we are going to need in our production and consumption patterns".

And the party's principal spokesperson went on to claim that the Greens were reflecting the real views of voters.

"On more and more issues, it is the Greens who are most in tune with public opinion," she said.

"From consistent and principled opposition to war in Iraq - to protection of public services from privatisation.

"From opposition to ever greater free trade - to better, more humane treatment for asylum seekers and refugees.

"From opposition to tuition fees and top-up fees - to urgent action on climate change.

"It is the Greens who are offering consistent and credible policies, backed up by the commitment to put them into action.

"And crucially, it is the Greens who are bringing honesty and integrity back to politics."

Despite delivering an upbeat message Lucas conceded the general election would be "hard for us as a smaller party facing a hugely unfair electoral system".

"But the only wasted vote is a vote cast for a party you don't believe in, which stands for values you don’t share, and implements policies you don’t support," she said.

"A vote for the Greens puts social justice and the environment at the top of the political agenda.

"And increasingly it elects Green politicians who demonstrate that it is possible to be radical and effective."