THERE seemed no obvious causal relationship, in the spring of 2003, between the US military offensive that had just been launched against Iraq, and two particularly aggressive horror movies that were released at almost the same time - Cabin Fever and House Of 1000 Corpses. In the four years since, directors Eli Roth and Rob Zombie (not his real name) have moved on from those respective debut features to become leading proponents of a cruel new subgenre, generally referred to as "torture porn", although Roth prefers "gorno", a term of his own devising.

This development has been so concurrent with reports and images of detainees being abused by American armed forces personnel that similarities between real andstagedscenesoffear,painand degradation now appearprogressivelylesscoincidental. Longer-serving horror director Joe Dante has gone as far as to describe a wave of recent releases - including Roth's second film Hostel, Zombie's The Devil's Rejects, James Wan's Saw and its sequels - as "Abu Ghraib movies".

Dante himself can't claim to be subtle in putting news headlines to work for his own purposes, having made a TV movie called Homecoming as part of last year's Masters Of Horror anthology series, in which US marines return from Iraq in flag-draped coffins only to rise up as zombie lobbyists, demanding voting rights and thus removing from power the government that sent them to their deaths. What troubles him, and other genre veterans, is the supposed "coarsening" of these younger film-makers and their audiences, whose capacity to supply and demand the explicit is making the content of these movies ever harder, and bringing that content ever closer to the mainstream of pop culture.

"Things have definitely taken a turn for the worse in the last few years," says Zygi Kamasas, CEO of film production and distribution company Lionsgate UK, whose upcoming slate of releases includes the backpacker-slaying Paradise Lost and the fourthintheexceedinglysadisticSaw series. His is an interesting choice of words - when Kamasas says "worse", he must also mean "better", commercially speaking. The "stronger, more extreme material" he is talking about has proven increasingly lucrative. Lionsgate are now market leaders because of their proven knack for financing, and particularly advertising, cheap, nasty and profitable modern horror franchises. If these movies are signs of the times, then so is the way they are sold.

"I don't necessarily think that the levels of gore we're seeing now is a new thing," says Kamasas. "Horror, like every other genre, is definitely cyclical and a lot of these films are throwbacks to the 1970s, which was the last golden age, if you like, of really explicit stuff. The difference is that those 1970s movies were hardly marketed at all, so relatively few people ever saw them. Even six or seven years ago, I don't think you would have seen the mainstream marketing of movies like Hostel and Captivity."

The latter film went on general release in the UK this weekend, but it has been a notorious case study since March, when it was briefly advertised in New York and Los Angeleswithacaptionedsequenceof photographspurportingtoshowthe "abduction", "confinement", "torture" and "termination" of a model played by actress Elisha Cuthbert. Those cities are twin centres of the US film industry and, not coincidentally, home to some of the broadest minds and tastes in America. The most strenuous and effective objections to the Captivity campaign,however,camefromvoiceswithintheentertainment business, principally Jill Soloway, a writer for the TV drama Six Feet Under, who called it "the most repulsive, horrifying, woman-hating, human-hating thing I have ever seen in public".

JossWhedon,creatorofBuffyThe Vampire Slayer, said: "This ad is part of a cycle of violence and misogyny that takes something away from the people who have to see it ... it's like being mugged." Within a week, the billboards and taxi-mounted hoardings were taken down by the film's production company After Dark, with an apology and the excuse that the wrong files had been sent to the printers, who supposedlyproceededwithoutauthorisation. Lionsgateweretheatricaldistribution partners on the project in the US, but denied any prior knowledge of the advert.

Their co-president of marketing Tim Palen, who is respected as an artist by horroraficionadosforhisinnovative, unnerving and influential poster designs, declared the Captivity images "vulgar" by comparison to the "elegance, flourish and technique" of his own work (consider his sly use of two severed fingers to advertise the first sequel to Saw). "Advertising by definition is exploitation," admitted Palen. "It's easy to shock people. But you have to know when you're crossing the line."

As a film, Captivity is nothing new, or even especially graphic by past and present standards of the genre. Although Cuthbert's character is terrorised throughout, her captor's methods are mostly psychological, and the producers themselves have been belatedly eager to stress that there is no rape or nudity in it. The ending has been reshot so that the heroine ends up in "more of a positive situation", and After Dark's own CEO Courtney Solomon has even claimed that this movie "is also about female empowerment". In other words, anyone excited by the promise of those misjudged billboards may find the actual product disappointing.

Anironicdownsideofthegenre's unprecedentedmarketability,suggests Kamasas, is that it requires each successive release to be advertised as more ferocious than the last, and more definitive an experience than a quickly-made cash-in is truly likely to be. "These films are so thrown in people's faces now, with TV spots, graphic posters, horrific quotes from the press, that it makes them more rather than less likely to say Oh, it's only a movie'." He doesn't thinkthiscurrentcycleofhardcore brinkmanship will continue much longer, citing a lack of "fresh, new" horror projects nowindevelopmentatLionsgate.He sounds almost glad.

"Well, it has got to a level where the shock factorisprettyextreme.Personally,I understand the question of whether we should, morally, be making these things. Our first duty, sadly, is to our investors and shareholders. Saw II was an even bigger success than the first, so you have to do another one. And if we hadn't made Saw or Hostel, then someone else would have. So then you're losing money on moral grounds. In business you need to deliver, and these films certainly do. But I do feel slightly torn."

The ugliness of the Saw films is at least partly down to this imperative. More disturbing movies were made decades ago by Italian maestros Lucio Fulci and Dario Argento, or Vietnam-era American troublemakers George Romero and Wes Craven (whose notorious 1972 debut Last House On The Left has recently been censored for DVD rerelease by the British Board Of Film Classification, while its modern equivalents nowtendtogouncutbecausetheir constituent elements of sex and violence are kept simple, separate, overt, and unambiguous). Even at their most unpleasant, however, these works were almost always theoreticallydefensibleongroundsof artistic or political intent.

In Saw II, the main - and maybe only - reason for the camera to linger on the sight of afemaledrugaddictswimmingand screaming through a drained pool full of dirty hypodermic needles is the plain fact that director Darren Lynn Bousman and writer Leigh Whannel are being paid to design and construct these excruciating set-pieces as if each one was a brand new patent.BBFCrepresentativeSueClark accepts that such scenes are "not everyone's cup of tea, but to people who understand thegenreanditsconventions,being appalled is part of the fun". "As long as the purpose of the violence is to horrify rather than titillate," she explains, "we're unlikely to intervene."

Videogames,beinginteractive,are apparentlyheldtoaslightlydifferent standard, and last week Manhunt 2 was refusedacertificateongroundsof "unremitting bleakness and callousness", a phrase which could equally be applied to anything in the Saw series.

Consciously or not, though, the machine-shop aesthetics, butcher-shop morality and sweat-shop market values of these movies probably tell us as much about our period of history as Romero's Night Of The Living Dead did about race and hate in 1968. Wes Craven,whoaddressedandexploited similar contemporary fears in his own early career, has explained the genre's resurgence in the most basic terms: "we're living in a horror show".

"The post 9/11 period, all politics aside, has been extremely difficult" said Craven, "We all know what's floating around out there and it expresses itself in a million ways, from people drinking a bit more to kids going to hardcore movies." Other, younger voices seem to wish it was really that simple.

Joss Whedon, for example, was less upset by the misogyny used to advertise Captivity (among the oldest and commonest criticisms of horror, only its blatancy seemed new or surprising in this case) than by the way it reminded him of the cameraphone footage which emerged earlier this year of Kurdish teenager Du'a Khalil Aswad being stoned to death by male family members in Bashiqua. As Whedon saw it, one of those men must have recorded this supposed honour killing for the same reason that a horror fan might watch something similar happen to a fictional character - "because it was cool" - and with an identical underlying assumption. "Women's inferiority and malevolence," he wrote on his website, "is as ingrained in American popular culture as it is anywhere they're sporting burkhas."

Eli Roth's new movie Hostel Part II, in which three female holidaymakers fall prey to businessmen who have paid for the privilege of torturing and killing them, has already been condemned along exactly those lines. Roth's generic defence - "any time people see women in a horror film they say, oh, these girls are just pieces of meat'" - may be read as further evidence againsthim,oravalidreminderthat imaginary crimes are victimless. "People assume these movies are made by idiots for idiots," he has argued. "They're not. These films are very subversive."

Horrordirectorsare sometimes as misunderstood as they often claim to be, and it's true that Roth's attitude has been widely confused with that of the lead characters in his first Hostel movie - sexist young American males, lured to a merciless rendering in Eastern Europe by their own decadence and ignorance. The cruelty of this joke was better appreciated in Slovakia, where the movie and its sequel are set, than in his home country, where the bulk of its audience belonged to the same demographic as those protagonists. If anything, Roth may be sharpening his point with Hostel Part II, in which both the girls and their attackers are American tourists, and all are made to pay for regarding the world as their own personal playground or torture garden.

The director, son of a Harvard psychologist, is obsessed not just with the form but the context of 1970s horror movies that inspire him, positing the explicitness of "gorno" as a response proportionate to those urgent scenes of real life and death that his countrymen find harder to look at. "It's sickening that we've not been allowed to see images of the bodies coming back," Roth said recently, before describing the letters and emails he receives from soldiers in Iraq "saying how much they love Hostel". "In the line of duty, you have to respond tactically, like a machine. You can't show any emotion. But when soldiers sit down to watch Hostel, they're not only allowed to be scared, they're encouraged. All those feelings come out."

This sounds like a specifically modern reworking of the oldest, simplest and shortest answer to the question of why anyone would want to watch this stuff: "catharsis". It's complicated by the fact that the real and original "Abu Ghraib movie", with its heavily sexualised and choreographed images of actual torture, was made by and for just such American soldiers, many of whom said more or less the same thing when caught.

At a conference on the subject in New York last week, Professor Adam Lowenstein, horror film scholar and author of Shocking Representation:HistoricalTrauma, National Cinema And The Modern Horror Film, argued that it is still far too early to know if "torture porn" will have any lasting value. But he ruled out the possibility that it will ever reconcile us to what we've done or seen. "Horror's dark gift," he said, "is to remind us that catharsis is too easy, too artificial, and too closed. We know from history that the events we think we've passed through and gotten over and understood come back to haunt us in all sorts of ways."

Captivity is out now, and is reviewed on page 20. Hostel Part II is released on Friday