The Green Left is an anti-capitalist and eco-socialist grouping within the Green Party of England and Wales. It seeks to constitute a network for "socialists and other radicals" in the Green Party, as well as "act[ing] as an outreach body that will communicate the party's radical policies to other socialists and anti-capitalists outside the party." It includes some prominent members of the Green Party of England and Wales, and held its first meeting on 4 June 2006.^[1] Green Left members were early supporters of an "ecosocialist international", such as the Ecosocialist International Network (EIN).^[2]

Green Left was launched on 4 June 2006 by members of the Green Party of England and Wales. Those who supported the group included various members of the Green Party of England and Wales Executive, including Richard Mallender (Chair), Peter Cranie (elections co-ordinator) and Siân Berry (at that time one of the two principal speakers, and campaigns coordinator), as well as Penny Kemp (former party chair), Joseph Healy (Secretary, London Green Party), Derek Wall (writer, and at that time the other principal speaker) and Peter Tatchell (human rights activist). Cllr Sarah Farrow and Cllr Matt Sellwood were elected as the co-conveners of the new group.^[1]

Green Left formulated its beliefs, agreed on at the meeting, in the Headcorn Declaration (below), which stated that Green Left hopes "to raise Green Party politics to meet the demands of its radical policies". The statement criticised the "New Labour government's abandonment of the policies of the left" and claimed "that the Green Party's progressive agenda makes it the natural home for the left".^[1]

In June 2006, 36 members of the Green Party agreed to the core beliefs and policies of the Headcorn declaration which became a launch statement of the Green left. The launch statement included the following points:^[1]