The Greens have overtaken the Liberal Democrats for the first time in a decade, in the latest poll which is certain to fuel calls for the party to be included in TV debates.
Research for Conservative peer Lord Ashcroft put the party on a new high of 8% - up three points - and just ahead of the Lib Dems on 7%.
The survey gave Labour a three-point lead over the Tories, 31% to 28%, with Ukip on 18%.
The data suggests an astonishing number of young people, 28% of 18-24 year olds, are planning to vote Green, though the poll only surveyed around 1,000 people.
The result may indicate that the Greens are likely to echo their success in the European elections, where they beat the Lib Dems, on a national level, though because of the first-past-the-post system, the increase in vote is likely to mean more Green candidates come second or third in constituencies, but do not win more seats.
The Party have been polling neck-and-neck with Nick Clegg's party for much of 2014 but this is the first time in a decade that the Party has edged ahead.
Almost 200,000 people have signed a Change.org petition calling for the Greens to be invited to the leaders' television debates prior to the 2015 general election. Current plans are to invite David Cameron and Ed Miliband to go head-to-head in one debate, for Labour, Lib Dems and the Conservatives to take part in another, and for the fourth debate to include Ukip's Nigel Farage.
Ukip have one seat in Parliament, the same number as the Greens.
"This poll result reflects the direction of travel of support for both parties in recent months," said Greens leader Natalie Bennett.
“The coverage of our exclusion from the leader debates under current plans has certainly given more voters a chance to hear a little about the Green Party, and learn about policies such as making the minimum wage a Living Wage, bringing the railways back into public hands and saying that the profit motive has no place in healthcare.
"Our membership surge indicates that they are clearly liking what little they have had the chance to hear and this further strengthens our case for inclusion in the debates."
Both Cameron and Labour's Ed Balls have both said they can understand the frustration at the Green Party about not having been invited to take part.
In a YouGov poll for the Times, 47% of voters said they would back the inclusion of the Green Party in the debates.