There are many things to say about Caroline Lucas, but even her fiercest critic cannot deny her tenacity. For the last 25 years, she has fought to move the Green Party out of the fringes of politics and transform it into what she calls “an electable vehicle”.

Under her leadership, the party has gained more publicity and credibility than at any other time in their 37-year history.

The greatest victory came in May this year with Lucas snatching election victory in Brighton Pavilion, beating Labour’s Nancy Platts and Conservative’s Charlotte Vere, to become England’s first Green MP.

The journey, she says, has been exhausting. “But exhilarating as well. Election night was certainly one never to be forgotten. It feels like the culmination of so many people’s work over so many years.

It really felt like all that effort and energy had come together.”

We meet in the cafe of Westminster’s Portcullis House, drinking tea out of House of Commons china. It’s certainly a step up from the last time we spoke, some four years ago, huddled in the cluttered spare room of a Green Party colleague somewhere in Seven Dials.

For the purposes of full disclosure, I’m not a Green voter and probably never will be, but I do find Lucas an impressive figure. With a trite media concerned more for the shoes our female politicians wear than their policies, Caroline has fought her ground as a fiercely intelligent, genuine, three-dimensional character, a million miles away from the tragic tokenism of Theresa May.

Now gleefully taking her place in Parliament, her politics remain consistent and unsurprising. She thinks the coalition is by and large a good thing but is also acutely aware of the lucky opportunity it has thrown up: “Which is the party speaking out against academies? Where is the voice actively opposing Trident? We know from surveys a huge number of Tories are sceptical about climate change. The Lib Dems are now in on nuclear power. You could argue the coalition makes my voice even more important.”

It does feel good to have a loud voice redressing the balance, but here’s the rub: to my mind, no one in the Green Party, and especially not Caroline Lucas, understands the first little thing about science or the scientific process. Their manifesto pledges a flood of investment in already discredited complementary therapies, wants to completely halt vital lines of research such as GMO, ignoring the incredible world-changing potential and focussing solely on the fear of misuse, and insists scientists of any discipline must take a vow of allegiance to the planet before being allowed to practice.

Caroline points out that many of the more flaky ideas have been considerably tightened up over the past couple of years, which to her credit is very true. There are still plenty of dangerous ideas though. Why would, say, a particle physicist have to swear an oath about something of no relevance to their field written by a government she may not have voted for before being allowed to work? It smacks rather too much of the top-down, dictatorial approach the party claims to detest.

So where does that leave matters? Caroline is impressive, her achievements are numerous. She’s a pleasure to sit and have tea with. She cares very much about vulnerable people and thinks rich people should help them out. She thinks the world would be a nicer place without oil companies and war and climate change.

She’s exactly the right MP for Brighton: educated, thoughtful, ethical to the end and ever so slightly bonkers. She is, I think, a little like an eccentric aunt: you’re very pleased she’s there, but you probably wouldn’t want her running the country.