I felt a little like Jason Bourne. After being pursued for ten minutes down the labyrinthine corridors of BBC Television Centre, a tall, suited and quiffed Mark Kermode finally collared me, sat me down in the 5 Live studios and got straight to the point. "I don’t want any other people to agree with me" he explains, and having seen some of his most ferocious critical lampoons unravel, I have no reason to doubt him, "everyone’s opinion is different, it just happens my opinion is right".

As anyone who has seen Dr Kermode on the BBC’s Culture Show or heard him on 5 Live will testify, he pulls no punches. His approach to film criticism is all out subjectivity, e.g., "The Exorcist 2: The Heretic is by far the stupidest film anybody has ever made. Ever." Soon followed up with a second bowlful of hyperbole – "I think Sex and the City 2 is actually corrosive, hugely offensive and really, genuinely bad".

Yet even in his condemnation, Kermode is inventive, witty and self-aware. It isn’t solely his cinematic gag-reflex that provokes the 47-year-old critic to respond as he does, but rather a firm belief in the subjective nature of all criticism, academic or otherwise. "There’s a load of people who’ve read my book or listened to the Mayo show and said that they were entertained, but completely disagreed with almost everything I said. To me, that’s perfect. As long as they’re entertained and understand that when I say these things, I mean them. I’m not saying Pirates of the Caribbean is evil just to be funny. I don’t think it is funny, I think it’s seriously bad for the world."

Described by the Scotsman as, "a feminist, a near vegetarian (he eats fish), a churchgoer and a straight-arrow spouse who just happens to enjoy seeing people’s heads explode across a cinema screen," it seems Kermode is keen to stand by all his choices in life. Unlike other media ‘doctors’ (Dré, Fox, um … Robotnik), our critic has a PhD in English. He wrote his thesis on horror fiction at the University of Manchester in the 1980s where he also engaged in the social and political uprisings of the period, committed then as now to making known his views on what is and what is not bad for the world.

Previously he had written books on specific films for the BFI, but never anything that captured the familiar, candid voice of his film reviews, something he has attempted to undo through a new book. "I wanted to write a book like I talk, it’s an autobiography written through the films I saw as a kid." The book It’s Only a Movie takes its title from the original poster of 1972 horror classic The Last House on the Left ("to avoid fainting, keep repeating, ‘it’s only a movie,’" as if anyone would ever doubt his belief that it’s only a movie.) "It’s a bit like that footballer who once famously said football isn’t a matter of life and death, it’s much more than that."

So how did this scholarly, socially-conscious young man ever end up as Britain’s best-known and perhaps most feared film critic? "What I did when I was a kid was I went to the cinema. Other people did things like played sport, went to parties and had girlfriends; I didn’t." After twenty years of reviewing films, it seemed fitting for him to tell his story through the films as he remembers them – though he tells me he doesn’t much bother with the distinction anyway. "I’ve never really distinguished between films and reality. As you live life it’s raw footage; you edit and construct a version of it which is the director’s cut of your life. But it’s only true for you."

Kermode upset some of our readers recently by knocking the University’s dominance in The Times’ international university rankings. The problem with these tables is that, unlike Mark, they are not prepared to admit the subjective element behind their findings – "don’t get me wrong, it’s a magnificent University, my mum and dad met at Cambridge, if it wasn’t for Cambridge I wouldn’t exist. But to say any university is better than all others in all disciplines is just plain stupid."

So what do his Cambridge alumni parents, both medical doctors, think of their son’s chosen career path? "The two pieces of advice my dad gave me when I was young were "stop watching all those films" and "learn to speak properly". I’ve always said I must be a great disappointment to him because I’ve made a living [by] speaking improperly about all those films."

Mark’s wife, Professor Linda Ruth Williams, is also a film buff, lecturing in Film at the University of Southampton. I wonder if having two outspoken film critics in the house ever brings them domestic unrest – "we tend to agree," he says, "but there was one occasion early on, that I felt, was a deal-breaker." The film was Lars Von Trier’s Breaking the Waves, a film Mark had given a scathing review, but which he was made to rewatch at the behest of his new wife. "We sat separately so my reaction wouldn’t bother her. As I saw it, I thought, ‘this is hateful, I really, really despise it. What am I going to do if she likes it?’"

In the black-and-white, right-and-wrong Kermodean universe, differences of opinion can be fatal. "We came out and there was silence, I looked at her and said, ‘so’? – ‘Bollocks’ came the reply, and I thought to myself, ‘that’s my girl’."

 Mark Kermode’s book, It’s only a Movie, is published on 4th November.