The Green Party is celebrating after more than doubling its vote share in the Brighton Pavilion constituency.
Keith Taylor now hopes to make history at the next general election
The seat was the Greens' number one target at the election after Keith Taylor came fourth in 2001.
Mr Taylor got their best ever result this time, finishing third and polling only 6,000 fewer votes than the winning Labour candidate.
He said his 22% share, up by 12.7%, signalled that voters had identified with his party's vision.
Mr Taylor admitted some people had probably sided with the Green Party as they felt they could not vote for Labour because of what he called "the Iraq factor".
But he said his success was not just down to protest votes.
"We got votes from people who identify with our vision and they understand that the Green Party is the only party trying to find policies and solutions for the next 100 years, not just for the next ballot box."
The Greens' targeting of the seat meant a good turnout of supporters at the polling station.
Brighton Pavilion topped five key Green constituencies at the election
"I think the campaign has gone fantastically in Brighton Pavilion," said Mr Taylor.
"The Green Party has seen volunteers coming from all over the country to help.
"We will come back in the next general election and, for me, I hope to be the candidate and we hope then to make history because now we've seen that we can do it."
Brighton Pavilion was held by Labour's David Lepper, with Mike Weatherley coming second for the Conservatives and Hazel Thorpe in fourth place for the Liberal Democrats.
Mr Lepper had said the Greens were being "wildly over optimistic" about their chances of winning in the constituency.
Brighton Pavilion results
David Lepper, Labour, 15,427 (35.4%)
Mike Weatherley, Conservative, 10,397 (23.9%)
Keith Taylor, Green, 9,571 (22.0%)
Hazel Thorpe, Liberal Democrat, 7,171 (16.5%)
Kimberley Crisp-Comotto, UKIP, 508 (1.2%)
Tony Greenstein, Alliance for Green Socialism, 188 (0.4%)
Ian Fyvie, Socialist Labour Party, 152 (0.3%)
Christopher Rooke, Independent, 122 (0.3%)
Keith Jago, Independent, 42 (0.1%)
"I think people recognise that they've already got a green MP for Brighton Pavilion and that's me," he said, after retaining the seat he first won in 1997.
"I am a lifelong non-driver, someone who has campaigned locally and nationally on all the important environmental issues.
"I think they [the voters] didn't see the reason to change a green Labour MP for a so-called Green MP."
However, the Green Party remain confident of future success after Mr Lepper's lead was cut from more than 16,000 votes in 2001 to 5,856.