Speaking during a visit to the EMMAUS Trust, Newark, Natalie Bennett said: "We are the anti UKIP vote. We take votes from the Lib Dems, Labour, and the Tories, and if people are disillusioned with those three parties then we are the party to vote for.
"We were pleased with the recent election results, particularly in some of the local council elections. We are now in direct opposition in Solihull for example, and we had strong results in the East Midlands."
"It's hard to tell how we will do in this by-election, but we have a message for real change and positive change. We are the only party who believes the NHS should be kept public, the only party to oppose HS2, and one of our main issues is being against fracking, which a lot of people are concerned about."
UNISON worker Mr Kirwan, who says he is the only local candidate within the main five parties, said he would campaign to stop fracking in the Newark area, pointing instead to solar panels as a better way to provide renewable energy.
Mr Kirwan said: "Although Newark doesn't have new sites for fracking, we know there will be planning applications for fracking in the next few years.
"It's important that people understand the repercussions of fracking, it's a short-term energy solution, and the fact that the government are planning to buy people out in exchange for drilling under their house tells you it's a bad idea. The Newark Advertiser.
AS I SAY, DON'T UNDERESTIMATE THE GREENS AND THEIR PROGRESS BASED ON OPPOSING FRACKING. UKIP'S BIGGEST MISTAKE IS SUPPORTING FRACKING, AND COULD COST THEM THEIR NEWARK BREAKTHROUGH. FRACKING IS NOT ON THE MSM RADAR, BUT IS BECOMING AN ELECTION TURNING ISSUE. WILL SOMEONE NOTIFY FARAGE PLEASE.