Clearly delighted by its two seats in the European Parliament, the party claimed it had finally broken through the "credibility barrier" and predicted that it could have MPs in the House of Commons within the next eight years.
The Greens' principal speaker, Jean Lambert, won a seat in the London region and Caroline Lucas was elected for the South East region as the party polled more than 500,000 votes across the UK.
In some areas of London, they came second ahead of the Tories and Liberal Democrats. The highest vote in the country was polled in Islington where 17.9 per cent of the electorate backed the party.
The British success was reflected across Europe, with Greens gaining seats in France, the Netherlands, Belgium and Austria to produce 32 MEPs, their biggest group yet in Strasbourg.
Backed by an eye-catching election broadcast, the Greens spent more than pounds 300,000 on what was widely seen as their most professional campaign.
Dr Lucas and Ms Lambert promised they would fight foranimal rights, fair trade and a ban on the import of genetically modified foods. They said their opposition to a single currency also influenced voters.
Dr Lucas said that with Labour and the Liberal Democrats "scrabbling to occupy the centre ground", the Greens had attracted voters who wanted a more radical approach.
The UK Independence Party, (UKIP) the other main beneficiary of the proportional representation voting system, was also celebrating yesterday as it paraded its three MEPs at a Commons press conference.
The party, which claimed it had been a whisker away from winning six seats, said it had taken votes from the Labour, Tory and Liberal Democrat parties. Nigel Farrage, the UKIP's chairman and MEP for the South East region, said the party was "nationist" not "nationalist" and wanted to pull out of the European Union.
Mr Farrage, Michael Holmes, MEP for the South West region, and Jeffrey Titford, MEP for the Eastern region, said they would take their seats but would put their travel expenses into a trust fund for "victims of Brussels bureaucracy".Reuse content