The Green Party has announced that its membership has doubled in the last 11 months.
The surge in support for the party - including an increase of around 500 this weekend following Natalie Bennett's appearance on BBC Radio 4's Any Questions - took it to 27,618 members this morning.
The party claims it is also polling at its highest levels ahead of a General Election since 1989, and says it is committing to stand in 75% of constituencies in May - a dramatic increase on 2010.
Bennett - who kicked off Bite the Ballot's Leaders Live season last week - described the growth a "real landmark" and said many of those joining are former Labour and Liberal Democrat members.
Natalie Bennett, leader of the Green Party, has said she will value having direct contact with young voters when she kicks off the Leaders Live events on Wednesday 26th November.
The Green Party have threatened to take legal action unless broadcasters explain why they have been excluded from the 2015 general election leaders' debates.
An online petition has now gathered 150,000 signatures urging for the party to be included.
At the moment the Conservatives, Labour, the Liberal Democrats and Ukip will be represented, although the eurosceptic party have only been offered a place in one debate.
Head of media Penny Kemp has written to four broadcasters - ITV, BBC, Channel 4 and Sky - arguing that the party has been unfairly left out of the debates.
Her letter also points out the Greens' strong polling performance, saying: “The Green party received 150,000 more votes than the Liberal Democrats in the 2014 European elections and won three times as many seats as them"
Green Party leader Natalie Bennett has cast her ballot in the local and European elections.
After being buoyed by the latest polls, the Green party hope to get their best ever result in the European elections, but it is a different case in Brighton, where it has been anything but a smooth ride.
ITV News political correspondent Romilly Weeks reports:
British politics is heading for "big shifts" in the next few years as voters abandon mainstream parties in the search for "new answers", the leader of the Green Party in England and Wales said.
Natalie Bennett was speaking as activists gathered for their autumn conference in Brighton.
Ms Bennett rejected suggestions the rise of the UK Independence Party had sidelined the Greens from their former position as the fourth party in British politics, insisting 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".
"Obviously our policies are very different, but people are looking for new answers, and we are going to see big shifts in British politics in the next few years," she said.
"What we are seeing is very much a shift away from the three largest parties."
Natalie Bennett has been elected the new leader of the Green Party in England and Wales in a ballot of party members today.
Caroline Lucas is standing down as leader of the Green Party. Ms Lucas - who was elected as the party's first MP in 2010 - said she would step down in September at the end of her second, two-year term as leader.
"We're lucky to have a wealth of capability and experience in our party. Now feels like the right time to step aside, to allow more of that ability to come forward and help the party to grow," she said in a statement on the party's website.
The Green party is celebrating solid results in today's local elections. They saw an overall gain of 11 councillors, and the successful defence of all their seats in stronghold Norwich.
The party's leader and only MP Caroline Lucas said the results showed the Greens were "growing in confidence and steadily building support".
Jenny Jones, the Green party candidate for London mayor, is currently heading for third place.