Once More, With Feeling
by Victoria Coren and Charlie Skelton
Fourth Estate £10.99, pp352

Pornography is a mass of contradictions. It exploits women, or it liberates them. It demeans sex, or it celebrates it. It provides a vital means of release, or it incites objectification and violence. It abuses vulnerable young people desperate for money, or it offers a valid and lucrative career. Its use and content should be regulated by the state, or left entirely to the discretion of consenting adults.

The debate rages on, while into this moral minefield stumble a couple of Hugh Grant-like characters, Victoria Coren and Charlie Skelton, armed only with an intellectual knowledge of pornographic cinema, a couple of video cameras and - crucially - a big book deal.

If Daisy Donovan and Louis Theroux confirmed the appeal of the ingénue thrust into an egregiously foreign environment and winning through on middle-class English bluster and apology, then Vicky and Charlie, old friends from Oxford days, take the genre to another plane.

During their working afternoons reviewing porn films for the would-be highbrow periodical the Erotic Review, companionably munching HobNobs on the sofa as they compare notes on Rocco's Anal Ski Vacation, it occurs to them that the majority of porn films have pitifully little storyline or character development, and that as professional writers they could almost certainly do it better.

And here begins the biggest contradiction of all: the authors are adamant above all else that the film they set about making is not intended to be a spoof: 'It is not ironic. We are not setting out to lampoon the genre; we are operating within it to the very best of our ability.'

This is all very well, but they have ignored one vital fact: that the project was funded by the book advance. It was the book, not the film, that was the grail of this particular quest, which means that their every move was undertaken with an awareness that it would one day be written down in a funny book about making a porn film.

The irony for Vicky and Charlie is that their flamboyant inappropriateness for this project - Vicky's father is a Radio 4 regular and a Times columnist, Charlie's father is a vicar - means that it is impossible for them to approach their subject with anything other than irony. Fortunately they are working in a fine tradition: there can be no more quintessentially English way of covering our sexual awkwardness than by making sex comic.

That said, it is a relentlessly funny book and I couldn't put it down. But it is almost exhaustingly funny, as if it's being performed as a stand-up show and the audience's attention will wander if a moment of pathos or serious questioning is allowed to linger. In one sense this doesn't matter - they have made it quite clear from the beginning what kind of tone the reader is to expect, and it is more Carry On Cinematographer than Naomi Wolf - but as thinking people they cannot help questioning some of the attitudes they encounter, as well as their own, and the reader might sometimes wish they would allow these thoughts room to develop, rather than appearing embarrassed by them and quickly swatting them away with a gag.

'Vicky's Crisis' is a case in point. It happens during casting in Amsterdam, where the pair are confronted with the realities of the porn industry. Instead of the assertive, self-sufficient porn actors and friendly, humane directors they met in LA, their own castings are conducted among Eastern European prostitutes and rent-boys - 'miserable needy "actors" who are stuck in porn because they've got no option, or because their threatening husband makes them do it' - and her vision of making a proper porn film that might still aspire to 'art' begins to appear as misdirected student whimsy - 'we're paying these poor needy people a small amount to make idiots of themselves in a glorified fourth-form play. Our humour forced onto uncomprehending, desperate people is not funny,' she remarks, in a rare moment of self-knowledge.

Charlie's response is that anyone being compelled to sell their talents for money is called capitalism. 'And we're not making Marxist porn here. (We did toy with the idea of making a porn version of Das Kapital, but then we thought, "Nah, that's been done to death.")' So the questions are comically dismissed, or at least semi-justified, and we still don't really know where the authors stand.

Happily for Vicky and Charlie, however, on the whole they are encountering the sunny side of porn. Though they hear at second-hand of women who have died through abuse on set, or of the high suicide or HIV rate, the people they meet are largely confident and liberal with a happy family life, campaigning for better medical care or working standards across the industry - women like American actress-turned-director Jane Hamilton, who prides herself on the non-exploitative ethos of her films. Jane becomes their role-model in seeking an affirmative answer to the self-imposed question 'Is it possible to make "good porn"?'

The answer, naturally, comes via a degree of Nick Hornby-esque self-discovery on the part of the authors, both of whom spend a great deal of time wrestling comically with their consciences about the endeavour. Again with deliberate exaggeration, their greatest burden of guilt is not over whether they are exploiting young prostitutes, but whether they are disappointing their parents. And although these moments are presented with heightened comedy, and the circumstances are so extreme, there is something touching and universal about the sentiments. We have all worried about not being good human beings, about letting down the people who care about us - it's just that we're not all prompted to these thoughts by watching 'the airlock' (you'll have to read the book) through an amateur camera.

In the end the authors are presenting pornography as morally neutral; open to misuse, certainly, but in the right hands, harmless entertainment made by people who enjoy sex for other people who enjoy sex. But the fact that they do allow glimpses into the dark corners of what is still for many people an exploitative and abusive industry, and then gloss over them, makes the reader feel slightly doubtful about whether such a complex subject can be viewed solely through the lens of knowing irony.

The authors may protest the purity of their pornographic intentions, but the film's first screening next week is to an audience of journalists and assorted media clever-pants who will almost certainly be slightly embarrassed about watching porn with their colleagues and will cover their embarrassment by laughing in a knowingly clever and ironic way. And this, if the authors are honest, is really their target audience - or at least their target readership.