THE Greens urged people to “vote big, vote brave” yesterday as they kicked off their national billboard campaign.

The launch of the posters had been scheduled for last week but was put back because the party’s contractor could not guarantee they would be ready on time “due to the bank holiday.”

The adverts were finally unveiled in the Brighton Pavilion constituency by sole incumbent Green MP Caroline Lucas and party leader Natalie Bennett.

Explaining the reasoning behind the Greens’ rallying call, Ms Bennett said: “The time for half measures is over.

“This country desperately needs bold changes to take us away from business-as-usual politics.

“More people than ever will have a chance to vote Green at this election. Our message is clear: don’t vote for second best, vote for what you believe in.”

Ms Lucas said: “Only the Green Party is willing to stand up to the Establishment parties on issues like climate change, a resilient economy and protecting the NHS.”

Her battle to hold on to her seat in Parliament received a boost yesterday when Queen guitarist Brian May joined her at a separate campaign event in her constituency.

The Greens’ campaign continues today with the launch of the party’s election manifesto at the Arcola Theatre in east London.

Following Ms Bennett’s infamous “brain fade” radio interview where she struggled to explain how her party would pay for new social homes, Green leaders have insisted the document will be fully costed.