After winning just 1 per cent of the vote in 2010, the Green Party are now polling at around 5 per cent. In the past four years they have won over 10-15 per cent of those who voted Lib Dem in 2010, and around 5 per cent of the 2010 Labour vote.

But who are the Greens and what do they stand for?

With just under six months to go until election day, we spoke to Natalie Bennett, leader of the party. Here are the 9 things we learnt:

1. Britain is in crisis

The Greens are thriving because of four “matching” and “interlinked” crises: “an economic crisis, a social, environmental crisis, and a political crisis”.

“We're really the only non-business as usual party.”

2. Ukip voters are “lashing out” like a “small child”

Are Ukip not also an anti-establishment party? Bennett suggested that those voting for them are:

“…simply lashing out, in the same way a small child, who’s a bit overtired and fed up, lashes out.”

"…with unemployment, with the fact that benefits are inadequate… it's understandable, it's an expression of anger."

3. There should not be a cap on immigration

“Should there be a cap on immigration?” We asked. “No”, Bennett replied.

“Actually, it’s probably worth expanding on that a little…”, she continued, “the government is attempting to put a cap on net migration” which is an “intellectual nonsense and a moral wrong”.

“I have huge sympathy with the fact that we’ve got a low wage economy, but that’s not caused by immigration. No immigrant arrives at the white cliffs of Dover and goes ‘I want to work for really lousy wages and be utterly exploited’. What we need is a decent minimum wage that’s properly enforced.”

4. Ed Miliband lacks conviction

To what extent is Ed Miliband offering anything like what he should be offering?

"Er, well, I think, you know, it's… Ed Miliband… Yes… [chuckles]… I think, that you know, it's very disappointing that he's not showing real leadership." Bennett began, haltingly, before concluding more strongly:

"There's not any sense of conviction of what kind of society he wants."

5. David Cameron has done one thing well

“Gay marriage … I think he showed some real leadership and some courage in taking on parts of his own party.”

Is there anything else to commend? Bennett quickly moved onto the “many worst things” he’s done. “The fact that he appointed Owen Paterson as environment secretary is deeply disturbing.”

6. Should the SNP be in the leaders debate?

Yes, said Bennett: “I wouldn’t be opposed to them being in.”

7. The Greens will not join a coalition

“You sacrifice your ministerial cars, but you get to keep your principles, and I think that’s what the Lib Dems did wrong.”

“Should we find ourselves after the next election or any point in the future [able to form a coalition]… our first idea isn’t a coalition, it’s a confidence and supply agreement.”

8. What do the Greens think about…

They are anti-academies, think the NHS is being privatised, and want to decriminalise prostitution, but will only commit to setting up a “Royal Commission” on legalizing drugs.

The war on drugs has, though, “definitively, clearly failed”.

9. Is Britain the best country in the world?

“I can answer this by my actions rather than words. I chose to be British, it wasn’t an accident at birth.”