An audience of Independent readers attacked Labour and the Conservatives for their increasingly "negative stances" on immigration.
"Immigration is too important an issue to involve it in party politics," said the Green Party candidate, Tony Juniper, at the debate in Cambridge.
The readers also grilled the panellists on the likelihood and merits of a hung parliament and plans to deal with the economic crisis, while the Mr Juniper called for a timetable for the withdrawal British troops from Afghanistan.
The Conservatives were described as being given a "protection racket" by certain sections of the media.
Panellists Julian Huppert, for the Liberal Democrats, Daniel Zeichner, of Labour, Nick Hillman of the Conservatives and Mr Juniper, as well as this newspaper's columnists Johann Hari and Steve Richards, met the public in an Independent Live debate.
Mr Huppert set out the conditions under which he thought his party could work with Labour and attacked the Labour government's record on civil liberties. "We have to have electoral reform as a minimum," he said, adding: "I would find it very, very difficult to come to a deal with a party as authoritarian as Labour have been." He said he thought any deal between the two parties would involve "getting rid" of some of the Labour measures that have been introduced limiting civil liberties.
One audience member said that he was surprised by the diminished role which women seemed to be playing in the election campaigns. Jamie Stern-Weiner, a 20-year-old student at King's College, added: "The most impressive [candidate] so far has been Caroline Lucas of the Green Party."
Today, The Independent's campaign to encourage election debate moves to the key marginal seat of Solihull in the West Midlands. Five candidates for the constituency will mount soap boxes in Mell Square at 12.30pm to face the crowd. All spectators are welcome.