“Huppert the Muppet, I call him,” says the cab driver taking me to see Cambridge’s most visible politician, Julian Huppert, Liberal Democrat MP for the city since 2010.

If Cambridge is in the news, Huppert will usually turn up, usually holding a banner or frowning in a photo. Over Lent Term, Varsity is profiling the main candidates vying to take his seat from him; today, Mr Huppert gets his say.

Huppert is 36 and comes from a strong Cantabrigian background. He remains a fellow at Clare in Biological Chemistry, though is on unpaid leave while an MP, and was once a fellow at Trinity where he studied as an undergraduate and PhD. He is a friendly, unassuming man. He quips that his desk is the one without a seat. Perhaps the metaphor is best left implicit.

I get straight to the point and ask him about his election chances: the most recent Ashcroft poll indicates his closest rival, Daniel Zeichner (Labour) leads him by one point, while across the country the Liberal Democrats are polling only slightly better than tuberculosis. That said, the bookies have the incumbent as the slight favourite.

“I think it will be a very tight race,” he says, “and it’ll be a question of whether people like my track record as someone who has worked for Cambridge and delivered for Cambridge.”

He does work hard in Parliament: They Work For You ranks him “well above average” for his participation in debates and questions, and he is in several all-party groups, as well as the Home Affairs Select Committee.

Yet Huppert cites constituency work as the most rewarding part of his position, talking at length about a constituent whom he had assisted in finding housing.

Huppert is banking on visibility and the incumbency effect to hold out against an expected Liberal Democrat wipe-out in May. In Ashcroft’s Cambridge poll, the Lib Dems trailed Labour and the Conservatives until Huppert’s name was prompted.

What about the cab driver, tired of seeing Huppert every time he opens a newspaper? Does he ever worry that constituents will get sick of him? He laughs. “I hope to avoid it,” he says sheepishly, though “people certainly say they see my picture quite a bit.”

Proud of his track record, he describes himself as a “Rawlsian liberal”, opposed to any concentrated power.

Unprompted, he raises the Lib Dem push on ‘revenge porn’ as a particular success. He says “it would never be on the front page of the newspapers... but is actually something that would make a big difference.”

His liberalism has not been absolute. Although he rebelled on secret courts and pushed for a Commons vote on the new regulations banning British producers from making certain types of pornography, he voted with the government on the Data Retention and Investigatory Powers Act. Why?

“We’ve reduced the number of organisations that are able to get access to your information... the amount of time information is kept for, [the] purposes for which information can be looked at [and set] up a privacy and civil liberties oversight board... I think it was a good liberal package.”

Would he have voted for it without those concessions? “Absolutely not. Without them, it wouldn’t have happened. In my mind, it was a liberal measure. It wasn’t the perfect measure... but there was no way of getting what I would most like to see passed.”

In this sense, Huppert sees himself as a representative, acting “in the best interests of the people of Cambridge and the values of the people of Cambridge”. I point out that this, of course, helps his re-election efforts. Quickly, he replies: “It’s also what the job is. I don’t think it’s as cynical as you suggest.”

Huppert comes alive when we talk about drugs. Recently, he co-wrote an article with Caroline Lucas, Green MP for Brighton Pavilion, advocating major reforms in UK drug law. I ask him to elaborate.

“The aim of drugs policy should be harm reduction... the traditional approach has been not to aim at harm reduction, but to aim at use reduction, and... that’s increased the harms.

“What I would do immediately is to decriminalise on the Portuguese model: possession [of] any drug is not a criminal offence. You can do that quickly and easily and say we should have police efforts, not focused on the users, but focused on the gangs. There’s a lot of very, very nasty, violent behaviour there... That’s the first step.”

And after that? “Globally, we have to break the power of the drugs cartels. The only way to do that is to move forward on a global basis towards a more sensible system.” Does he mean legalisation? “The best outcome? I don’t know.”  In the end the scientist trumps the politician: on drugs he is anxious not to prejudge regulation in the US and Uruguay.

“The big question about legalisation  is what happens to usage. I strongly suspect that usage will not go up in the long term... I think we can wait a couple of years and find out.”

“Huppert the Muppet” seems unfair. He comes across as a Cantabrigian intellectual, for good and for ill. Whether that is enough for this crucial marginal as all eyes turn towards 7th May is another question entirely.