Addressing the Greens' autumn conference in Brighton, Ms Bennett predicted a "big shift" in British politics in the next few years as voters abandon the mainstream parties in the search for "new answers".
Ms Bennett rejected suggestions that the rise of the UK Independence Party had sidelined the Greens from their former position as the fourth party in British politics, insisting that it marked a general shift in politics away from traditional party loyalties. Speaking to BBC Radio 4's Today programme, she said she had been told that in many cases voters were "talking about Ukip and Greens in the one breath".
In her speech, Ms Bennett ranged far beyond the Greens' traditional environmental priorities to denounce the involvement of private sector "corporate bloodsuckers" in NHS healthcare provision and promise to campaign against the "aching poverty" reflected in growing use of food banks.
"When history looks back on the Coalition, what will stand out is its failure to find a new economic model for Britain", she said.