Natalie Bennett has insisted she is the right person to lead the "second stage of the green surge".
The Green Party leader, who finished third in Holborn and St Pancras, did not follow other leaders Ed Miliband, Nick Clegg and Nigel Farage in standing down after her party gained one Westminster seat.
She said it had firmly established itself on the national scene after winning 1.1 million votes - up from 285,000 in 2010 - and finishing second in four seats .
She told BBC Breakfast: "What we have done is very much establish ourselves as a national party as part of the national political force. So for us, we've had the first stage of the green surge and what I'm aiming to do from today onwards is build the second stage of the green surge.
"We've had a good start in the last 24 hours - we've had about 1,000 more people join the Green Party so our membership has gone over 63,000, which means we are much bigger than Ukip and the Liberal Democrats."
On failing to win her own seat, she said: "In terms of the seat I was standing in, Holborn and St Pancras, I was always very clear I had a huge mountain to climb. I stood in the seat where I live, where I stood in 2010 and where I've been a community campaigner. It was the right place for me to stand."
The Green Party's sole MP Caroline Lucas was re-elected to Brighton Pavilion on an increased majority, winning 22,871 votes, against Labour's effort of 14,904.
Meanwhile the party failed to take its key targets of Norwich South and Bristol West - though it polled a respectable 17,224 votes in the South West city, taking it to second place.
But Ms Bennett also said the party managed to save more than 100 deposits, more than ever before, and also made gains in council elections, increasing its presence in Bristol and Cambridge.
She admitted being surprised by the overall result of a Conservative majority and hit out at David Cameron's party.
"Where we are now is a real cause for concern for the face of the disabled, the disadvantaged in our society, the fate of our public services and indeed what we are going to be doing about climate change but we will have Caroline Lucas there as a very strong Green MP," she said.
Comments: Our rules
We want our comments to be a lively and valuable part of our community - a place where readers can debate and engage with the most important local issues. The ability to comment on our stories is a privilege, not a right, however, and that privilege may be withdrawn if it is abused or misused.
Please report any comments that break our rules.
Read the rules hereLast Updated:
Report this comment Cancel