When, in May 2010, Caroline Lucas was elected as MP for Brighton Pavilion, it was a watershed mark for the Green Party. Never before had her party – which had been doggedly campaigning for around 20 years – played a part in mainstream British politics. This event followed a trend which had seen green issues gradually become hugely prevalent in politics. They have now become a necessity in the manifestos of all the main national parties.

Before we got down to the gritty business of parliamentary politics, however, I asked the leader of the Green Party to trace the history of her beliefs. “I first became interested in green issues through the anti-nuclear movement,” she told me. “In the mid-80s I was very involved in CND (Campaign for Nuclear Disarmament), which is where I became politically aware of the risks associated with nuclear weapons, and by extension, nuclear power.”

She cites one book in particular as having greatly influenced her views – “the critical moment really was reading a book called ‘Seeing Green’ by Jonathon Porritt, which I read in 1986. It was a real light-bulb moment; he analysed the environmental impacts of the way we live today, but also made very strong political recommendations for how to change it. It made complete sense.”

So it would be fair to say, then, that Lucas’s awakening to environmental issues stemmed from both intellectual roots, and from more active involvement in the campaigning side of the movement. Both sides of her character, moreover, are still very much visible today. When she speaks about policy, for instance, Lucas reveals an incredible articulacy and intelligence. Yet when she is asked about her current views on nuclear power her passion and zeal are still manifest.

“The idea that we need nuclear power in this country is utterly misguided and can’t be supported by the facts,” she states firmly. “My argument about nuclear power is that it is unsafe, uneconomical, and more than anything, unnecessary… It is just one of the most expensive ways you can imagine of getting our emissions down and keeping our lights on.”

George Monbiot, author of ‘Heat: How We Can Stop the Planet Burning’ and leading columnist on The Guardian, has recently come out in favour of nuclear power. As one of the highest-profile ‘greens’ in the country, he has attacked nuclear energy for years, arguing along very similar lines to Lucas. Oddly enough, it was in the aftermath of the Fukushima crisis in Japan that Monbiot did a U-turn and decided that he was wholly in favour of nuclear energy, claiming that the anti-nuclear lobby had for years been advancing arguments which were “ungrounded in science, unsupportable when challenged, and wildly wrong”.

These types of accusations, coming from a man who has been so staunchly and publicly anti-nuclear in the past, are surely damaging to the cause? Caroline Lucas takes a more intellectual approach this time: “In a sense he [Monbiot] is presenting us with an alternative, asking us whether we want climate change or nuclear power – but that is a false question. If you don’t have nuclear power, it does not mean you are locked into fossil fuels.” Lucas believes that the key to reducing emissions is in energy efficiency and energy conservation; “it might not sound very exciting, but actually it could make a massive difference”.

This might sound reminiscent of the old green movement, which seemed more concerned with reaction than progress, but Lucas is forward-thinking, and the Green Party’s policies seem to reflect her progressive attitude. “Technology” and “investment” are words which recur constantly in her speeches. In particular, her attitude towards big business is a million miles from the latent distrust and negativity of some of the older relics of the green movement.

“The private sector has an enormously important role to play,” she argues, “when it comes to being positive in this transition to a low-carbon economy.” While she admits that often it is ‘big business’ that hinders progress and reform, she believes this opposition is misguided – “the irony is that a transition to a greener economy is likely to be good for business, good for jobs, and good for the economy more generally.”

It seems, however, that at the moment this message is falling upon deaf ears in parliament. Lucas told me that she is frustrated with a coalition that came into power promising to form the greenest government ever, and yet has until now only delivered “a catalogue of missed opportunities and negative policies”. She cites the scrapping of the Sustainable Development Commission, cuts to the feed-in tariffs for the solar power industry, and the ineffectual nature of the promised Green Investment Bank as reasons for her disappointment.

“The biggest tragedy of all is that the government at the moment seems to think that environmental action is somehow in contradiction to a positive economy, whereas we would argue that if you want a strong and stable economy, the best way to do it is precisely through investing in green technologies.”

Getting this message across is one of her main priorities in parliament at the moment. As the government deliberates over whether or not to build a new fleet of nuclear power stations, moreover, Lucas is determined to see the money put towards the development of renewable energies. It seems, however, for the time being as though the circumstances are against her.

Aside from green issues, Caroline Lucas has recently been particularly vocal in debates over parliamentary reform. The Green Party was, perhaps unsurprisingly, in favour of AV. When I conducted this interview, the referendum of 5th May was still far from a foregone conclusion. Lucas’s warning is perhaps more ominous and poignant now than it was when she voiced it a few weeks ago – “my fear is that a ‘No’ vote will be interpreted by the government as meaning that the public don’t want any kind of electoral or constitutional reform, and it will set back the case for that reform by at least a generation”.

On 5th May we may well have also set the Green Party back from achieving the parliamentary recognition that they perhaps feel they deserve. Nonetheless under the leadership of Caroline Lucas the party has come far, and there is no reason to believe it won’t continue to progress from here.