Bosses of energy companies have been branded "robber barons" by the new leader of the Greens as she addressed the party's annual conference a day after her election.
Caroline Lucas was chosen as the first ever leader of the Green Party of England and Wales in a vote of party members, after a referendum last year scrapped their previous system of two principal speakers - one male and one female.
She used her first speech as leader to call for a windfall tax on energy companies and demand a "Green New Deal" of massive investment in renewable technology and energy efficiency.
Ms Lucas told the conference in London: "Just three companies - BP, Centrica and Shell - together made £1,000 profit every second over the first six months of this year.
"These corporations are robbing from the poor to give to the rich and they know it. And it's about time they learned that, in a progressive democracy, there is no place for robber barons."
She called for a Green New Deal to deliver public investment in "green-collar" jobs in areas including renewable energy, which she said could create hundreds of thousands of jobs while helping the fight against global warming and cutting fuel bills.
And she gave her backing to a programme of free insulation to every home in Britain.
"When the world faced economic depression back in the early 1930s, it was (US) President (Franklin) Roosevelt's New Deal that got people back to work with a massive investment in infrastructure," said Ms Lucas. "Today we stand on the brink of a triple crisis - a combination of a credit-fuelled financial meltdown, accelerating climate change, and soaring energy prices. We need a Green New Deal in response.
"The core would be a 21st century project to make the nation's buildings truly energy-efficient, with local authority bonds being issued to raise the necessary funds for a major investment in insulation, efficiency and renewables, creating hundreds of thousands of jobs in the process."
MEP for South East England since 1999, Ms Lucas is the party's candidate for its target constituency of Brighton Pavilion in the General Election expected in 2010.