Green Party leader Natalie Bennett speaks during a press conference to launch the party's election campaign in London on February 24, 2015. Bennett insisted the general election would be the "biggest, boldest campaign ever" for her party and told reporters that 90% of voters in England and Wales would have a local Green candidate. Bennett has admitted suffering a "mind blank" after a car-crash interview on radio in which she appeared unable to answer questions about key policies. AFP PHOTO / JUSTIN TALLIS        (Photo credit should read JUSTIN TALLIS/AFP/Getty Images)