“You’ll never have more freedom or more time than when you’re at university – ‘oh I’m doing my studies!’ – no you’re not, you’re in the fucking bar.” This was how Stephen Merchant, the BAFTA- and Golden Globe-winning writer and comedian, appealed to Cambridge students to make the most of their opportunity to dive into a career in comedy.

Merchant, ironically, told the packed Union Chamber that he wishes he had been sitting where they were twenty years ago, having been keen on the idea of coming to Cambridge – he tells me he would “study philosophy probably” if he could choose now – and joining the Footlights. He says he was “gutted” when his teachers persuaded him that he wasn’t academically good enough but then got the requisite grades for Oxbridge anyway.

However, despite being only “marginally” funny at school, he never gave up on comedy, saying that it “never occurred to me not to give it a stab.”

Throughout the evening the self-described “comedy nerd” won laughs effortlessly as he divulged carefully rehearsed anecdotes. Rapturous applause greeted one particular story that involved an infuriating small child throwing a shoe into Merchant’s soup at a wedding. When the apologetic mother light-heartedly asked “Oh, what’s he like?”, Merchant retorted “He’s like a cunt.”

However, such brazenness is far from the norm for the comedian, who concedes that he’s typically very awkward with people, such ineptitude being particularly acute when around women, as his show Hello Ladies parodied. Now 41, he passed on his romantic wisdom to the students present, telling them that they shouldn’t “be scared of girls” because “they’re like a bear in the woods – just as scared as you are of them.” Having had his own complications in the dating world – he jokes that in the past he used “would you like to meet Ricky Gervais?” as a chat-up line – he thinks standing out isn’t that difficult because “everyone’s an asshole, and if you’re not an asshole, you’re a step ahead.”

It would be hard to class Merchant as an asshole – throughout the evening it was clear that he’s still down-to-earth, saying that being a celebrity “doesn’t banish any personal demons you have” and admitting that when The Office went big he was “just swept along” with it, astounded that he was getting paid to write comedy. Did he wish he’d starred in it? “Yeah, when I saw all the free shit that Ricky got sent!” he jokes.

When we spoke afterwards, he says he isn’t at all involved in Gervais’s revival of the character that made both their names both in the UK and US, David Brent. Inevitably, Merchant did not escape the question he’s most asked about what many perceive to be another of his ‘characters’: is Karl Pilkington real? “Karl is like that, he’s one of the most unique beings I’ve ever met.” In validation of this, Merchant recalls a time when he, Gervais, and Pilkington were talking about celebrities who had become famous via their parents – such as Bianca Gascoigne and Calum Best – when Pilkington, in a “moment of genius”, cut them off by saying: “well, you could say the same about Jesus?”

Merchant, now residing in L.A., has noted dissimilarities with his native land since moving, finding Americans “more generally optimistic”. He adds that the UK is the only place where someone can shout affectionately: “Steve, you lanky twat!” – the kind of behaviour he feels wouldn’t sit well with Americans.

Unfortunately for the funnyman, living in the US means confronting an unfunny prospect: Donald Trump’s presidential candidacy. He finds the idea “terrifying”, and mocks the outspoken billionaire for having gone bankrupt and losing more money than if he’d just invested his inheritance.

How does he explain Trump’s rise? “There are so many fuckwits in America”, he replies, adding that there is a “weird anti-intellectualism” in the country. When an American student in the crowd jokingly protests against this, Merchant reassures him: “you’re not a fuckwit, you go to Cambridge!”

Talking after the event, Merchant says that people like Trump and Jeremy Corbyn are appealing to “disillusionment”, that “they fill this gap for people that feel like they’re not being spoken to” and, he adds with some enthusiasm: “it’s quite exciting”. As for his own political views, he tells me that he’s “not cynical about politics”, thinking that it’s “important that people vote and engage in politics”.

As for his heroes, the Warwick graduate mentions John Cleese – with whom Merchant shares both height and a West Country background that encouraged him that he could make it – as well as Woody Allen and Monty Python, famous for pushing the boundaries. Does he think we can draw lines when it comes to comedy? He does, but thinks “policing” comedy is “dangerous” because you inevitably “stifle creativity” and “that isn’t healthy”.

Merchant himself has not escaped criticism of overstepping the mark, describing how one celebrity refused to feature in Extras, calling the script “depraved filth”. He recalls that when Kate Winslet appeared in the show, she found one line – “something like ‘I’m sweating like a child molester’” – too much, but insists that he and Gervais never purposely sought to “stitch people up”.

Speaking after the event, Merchant was affable, generous with his time and – unsurprisingly – immensely tall. He’s not always “switched on” either, saying he’d much rather have a civilised conversation than be endlessly cracking jokes as some comedians do. When I ask him if he feels comfortable in the ‘Hollywood bubble’, he says that “it’s nice to put on a tuxedo and take your parents along”, but he finds celebrity award shows “absurd”. He adds that the novelty of the celebrity world “quickly wears off”, whereas the “novelty of sitting in a room writing has never worn off.”

However, he describes how he found little time for writing last year because he was on stage eight times a week, starring in The Mentalists in London. He took on that challenge because he wanted to do some real acting with the “discipline” of a fixed script, as opposed to the more improvised comedy he’s used to. “I hated it”, he says, “never do a play”. Is he joking? No, he truly found it exhausting – his own mother said he was “looking grey” – and miserable: “why can’t we change the words every night?”

It’s safe to say he won’t be acting on stage again any time soon. Instead, he’s currently “working on a couple of screenplays”, and our time is cut short because he needs to get on with writing them.

As he says just before leaving: “in the end, almost everyone I’ve ever met in Hollywood –­ if they’re any good – they are working really hard, and it’s not working hard to walk down a red carpet”.