Depending on which theorist you choose to consult, there is some disagreement on the difference between the terms docudrama and drama-documentary. The smart money has it like this: a docu-drama is a dramatic recreation of actual events, whereas a drama-documentary utilises the techniques of the documentary format to present a fictional, often future event, usually one based on research and presently acknowledged fact.

In his distinguished career as a film-maker, Peter Watkins has made genre-defining films from both of these categories. His 1964 Culloden, made for the BBC, was a recreation of the notorious 1745 Battle of Culloden and its appalling aftermath, but filmed as if a TV news crew had been present to witness the event and interview the participants. Made on a shoestring budget with a small cast drawn partly from Watkins' Canterbury theatre group, it chillingly conveyed the horror of battle and the terrible mistreatment of the defeated Scots, using techniques that were already becoming familiar to audiences via TV reporting of the escalating war in Vietnam. The following year he employed a similar approach to the BBC commissioned The War Game, a devastating supposition of the effects of a nuclear strike on South-East England, presented in sometimes horrifyingly realistic manner. It was too much for the BBC, who refused to screen it, but a technical loophole allowed it to be shown in cinemas and pick up a number of prestigious awards, including an Oscar for Best Documentary Feature.

Watkins continued to develop his faux-documentary style on a larger budget with his next two films, Privilege (1967) and Gladiators (aka: The Peace Game 1969). But in 1971, at the tail end of two years spent in America spent researching and writing The State of the Union, the first part of a filmic trilogy for the Learning Corporation of America that ultimately fell by the wayside, he made Punishment Park. This very much represented a return to his filmic roots, being shot in three weeks on 16mm with a cast of non-professionals for just $66,000. When it opened in San Francisco, it ran for just ten days before being withdrawn. In New York it lasted just four days. After a screening at the New York Film Festival, it was greeted with such hostility by the East Coast critics that no distributor, no cinema, would touch it. Having returned to the low-budget film-making of The War Game, Watkins was also to re-experience the repression of his creative endeavours. Now, thirty-four years later, a new theatrical print and DVD release has made the film available for retrospective re-examination. And guess what? It's a stunner.

Watkins' early films had a profound effect on me when I first saw them. I caught The War Game at the Scala in London and left the cinema in a state of shock (one accentuated by its double-bill teaming with Sidney Lumet's sobering Fail-Safe). At a time when the fear of nuclear war was still all too real, this was the only film I had seen that actually dealt head-on with what the probable effects on ordinary people would be. Years later, I screened one sequence for a group of students for whom the whole concept of nuclear war had become an almost abstract notion, and as I switched on the lights there was a collective exhalation of horror.* I first tracked down Culloden on a battered 16mm print and was so affected by it that I made a point of extensively researching this shameful episode in English history and even visiting the site of the battle, now a memorial to the fallen. Both of these films clearly resulted from Watkins' own reactions to specific events and attitudes, but, brilliant though they are, neither have the level of ferocious anger and sense of purpose that drives Punishment Park.

At the height of protests over the escalating war in Vietnam, the US government has invoked the 1950 Internal Security Act (known as the McCarran Act) to deal with incidents of internal insurrection by setting up of a series of detention camps, to which arrested protestors and political agitators are taken. Here they face judgment without trial, a chance to answer for their supposed crimes, and are presented with the choice between a long prison sentence or three days in Punishment Park, a 53 mile trek on foot across scorching desert terrain without food or water. They are given a one hour start, then are pursued by armed police and National Guardsmen. If caught, they are taken back to serve their sentence. If they reach the flag at the end of the journey they go free. If they resist, they are shot.

Watkins provides no build-up here, no traditional establishment of and identification with character and no plot preamble – Punishment Park kicks off in a state of conflict that doesn't let up for a single second. As Watkins' own voice-over outlines the situational details, the members of group #638 are paraded before the tribunal, protesting angrily, in a field tent erected purely for this purpose, then engage in individual verbal conflict with people who have already passed judgment on them. At the same time, the unfortunates of Group #637, who have already been sentenced, are set loose in the desert and flee for their lives, as their armed, soon-to-be pursuers pass their time chatting and demonstrating their shotgun and pistol skills.

We are informed early on that the proceedings are being recorded by British and German TV crews, and it is through their eyes that the proceedings are observed. Watkins again employs the techniques of drama-documentary that he has used so successfully in the past, but here it is honed to perfection, creating a startling sense that what we are watching is for real. This is achieved through a combination of savvy casting, extensive but inventively guided improvisation, and Joan Churchill's superb handheld camerawork.**

The casting in particular is crucial to selling the characters and situation as chillingly authentic. Watkins used real protestors and activists to play the prisoners and gave them free range to present their own viewpoints in their own way. He also incorporated elements of the 1968 Chicago Seven trail and based characters in part on key symbols of 60s youth protest, including singer Joan Baez, Black Panther leader Bobby Seal, and Chicago Seven defendant Tom Hayden. Similarly, those playing the tribunal members had little or no acting experience and were primarily of a more conservative viewpoint, but asked by Watkins to take "a few steps to the right" in order that the two sides not be able to see eye to eye on anything. Even those playing the police included in their ranks a number of ex-law enforcement officers. By priming the cast beforehand but keeping them separated until the filming of the tribunal sequences, Watkins creates a situation in which the views and anger expressed are largely real, resulting in a highly adversarial atmosphere that is consistently unsettling and sometimes genuinely disturbing.

As the behind-camera voice of the British TV crew, Watkins the director interacts with the characters by questioning them about the process they are caught up in, but later the thin line that separates reality and fiction all but breaks down as he comes into direct conflict with them, most jarringly in a sequence in which the actors playing the prisoners begin throwing stones at those playing approaching National Guardsmen, prompting the officers to respond by opening fire on them. As two protestors fall to the ground, Watkins can be heard screaming to Churchill to cut the camera, apparently under the belief that the stone-throwing, which had grown out of the genuine tension between the two opposing groups of performers, had prompted a for-real shooting that had left two of his cast dead.

As both Watkins and his biographer Dr. Joseph A. Gomez have been right to point out, Punishment Park is not a political diatribe, but a warning of the consequences of a failure to communicate. The arguments presented on both sides in the tribunal will be familiar ones to anyone who has been involved in political protest and are often coherently voiced, but neither side is interested in what the other has to say and argument rapidly degenerates into shouting matches and verbal abuse. That this was completely misread on its release and the film condemned as anti-American and even pro-Communist does seem somewhat inevitable, given the establishment standing of many of those from whom the complaints most loudly hailed and the American origin of most of the film's real-world references.

Whatever arguments are presented, the situation itself plants our sympathies firmly with the defendants, all of whom have had their constitutional rights ignored and been pronounced guilty without trial. Both sides ultimately resort to shouted rhetoric, but while the defendants are sometimes articulate and even witty in their responses (Jay Kaufman in particular runs rings round the tribunal, turning their questioning back on them and, when asked to define what he means by the word chauvinist, providing an eloquent lesson in the English language), rhetoric is all that the tribunal members have, which is used to berate the defendants in a manner that directly recalls footage of the 1950s McCarthy tribunals. References are made to the Kent State protest, where four students were killed when National Guardsmen fired live ammunition at the assembled crowds, and to the treatment of Bobby Seal in what was initially referred to as the Chicago Eight trial (it became the Chicago Seven after the decision was made to try Seal separately) – the shocking decision to have Seal bound and gagged to silence his outbursts is recreated here. Given all this, is it any wonder that the defendants resort to abuse so rapidly? Right from the start their anger feels not only justified but a last act of defiance. They know they are beaten, but they are not going to go quietly.

At the same time, those in Group #637 (these numbers provide a simple but powerful suggestion of the scale of this operation) effectively become prey in a primitive manhunt, their one hour head-start rendered largely ineffective when the police are equipped with jeeps and cars. A barbaric practice at best, this recalls the human hunt in Irving Pichel and Ernest B. Schoedrack's 1932 adaptation of Richard Connell's The Most Dangerous Game, a title referenced by the game motif that runs throughout Watkins' film. As the prisoners are lied to, cheated, threatened and shot, the fact that they resorted to violence first (used by Gomez in his commentary to suggest a level of balance) passes into relative insignificance, an act of desperation by more militant prisoners convinced they are themselves soon to die.

Watkins' trump card is his editing technique, cross-cutting between the two groups of prisoners and the hunters at a breathless pace, the juxtaposition of dialogue, sound and imagery creating a masterpiece of symbolic and subtextual sociopolitical commentary, which even at its least subtle is still utterly persuasive. The effect is underscored by the use of distorted music and sound effects, some of which become increasingly disconnected from the on-screen action, and are used solely to create an apocalyptic sense of civilisation in complete and utter free-fall.

Perhaps the most surprising thing about Punishment Park, given the year it was made and its main points of reference, is just how little it has dated. Sure, the hairstyles and some of the language may be very much of its time, but the cinematic and dramatic structure is as fresh as when the film first appeared, a boast few of its more celebrated contemporaries could make today. Even more striking is its political relevance, which if anything has become more potent in the intervening years and is emphasised by the precision timing of this DVD release: the holding of prisoners in denial of constitutional, legal and basic human rights by the US government has found its real world equivalent in the Guantanamo Bay camp in Cuba; the US Patriot Act has begun the process of restricting the freedoms of ordinary citizens; the rhetorical shouting down of anyone whose views differ from the voice of the establishment right has become an unpleasant feature of American radio and television; and the suffering of contestants on a depressing range of modern reality TV shows is now a worldwide and gladiatorial entertainment.

Whether the film will find a sizeable audience any more sympathetic than the one that rejected it back in 1971 is another matter. In America, an increasing shift to the right has seen a disenchantment with sixties radicalism and idealism, and even in Europe the once active youth protest movement seems to have lost its spark. (As someone who was a very active protestor in years past and has remained politically involved to this day, I find it somewhat depressing that the two most noteworthy expressions of political dissent in the UK in recent years were to protest the cost of filling your car with petrol and the right to hunt and kill animals for sport.) There's a very good chance that many of those seeing the film for the first time will never have been politically active at any level nor engaged in (often frustrating) public debate on political or moral issues, and will thus regard the characters and conflicts here as somewhat distanced from the real world. They are not. Watkins' film is as relevant as it ever was, a chillingly forward-looking fable not just for his own time, but for ours, a story that takes place, in Watkins' own words, "tomorrow, yesterday, or five years from now." Joseph Gomez regards Punishment Park as second only to the extraordinary Edvard Munch as the director's finest cinematic achievement. Despite the very real greatness of both Culloden and The War Game, I would have to agree.

Framed in its original ratio of 1.37:1, this is an astonishingly good transfer. Given that the film was shot on 16mm and blown up to 35mm, a degree of grain is expected, but it is never intrusive and, unlike on many transfers from 16mm prints, has not been exaggerated by compression artefacts or edge enhancement. A hair that can be seen on a few of the shots at the top of frame looks very much like it was in the camera and would thus be on all prints – it's never really distracting in any way. Colours are bang on – the dingy browns of the tribunal tent are deliberate – and the contrast, black levels and detail are excellent. A yardstick for just how good low budget, 16mm transfer can look on DVD.

Again, though a mono soundtrack is expected, the clarity and dynamic range of the Dolby 2.0 track included here is very impressive and belies the film's low-budget.

Optional English subtitles for the deaf and hearing impaired are available.

A commentary by Dr. Joseph A. Gomez, author of the book Peter Watkins, provides plenty of information on the casting choices, the technical aspects, and the improvisational approach to the performances and staging of scenes. Gomez also gives us his firmly held views on just what the film is about and why it has been repeatedly been misread, breaking down individual scenes in terms of their technique and effectiveness as cinema. Though there is some overlap with the contents of the included booklet, this is still an essential listen, whether you bought into Watkins' message or not (especially if not, I'd suggest).

The Introduction to Punishment Park by Peter Watkins (27:21) starts deceivingly with three-and-a-half minutes of scrolling text, but then gives way to a talk to camera, read from a prepared text, by Watkins, who no longer gives interviews because of past misrepresentation of his comments by the media. In that context, this is a rare and valuable inclusion, to hear Watkins' words from his own mouth as he discusses the film, its hostile reception (he even reads from some of the more negative reviews), and its continued relevance today.

Finally we have a typically excellent booklet, something that has become a standard and keenly anticipated accompaniment to all of Eureka's Masters of Cinema releases. I'm used to them being packed with information, but this one is really loaded, the standard 32 pages being even more crammed than usual, thanks to the use of a typeface small enough to make me glad I now have reading glasses. Really glad, as it happens, as the content is fascinating and includes an introduction by Watkins and a detailed outline of how the film was made, both from the original 1971 press kit; a self-conducted interview by Watkins, done in June of this year; and what looks like the entire chapter on Punishment Park from Dr. Joseph A Gomez's book on the director. There is some overlap with the commentary, but there is still plenty of fresh ground covered, and it includes a 2005 postscript by the author.

I am aware that I am coming from a political standpoint of my own here and that any audience is going to bring that to a film like Punishment Park, but for my money this has to be the cinematic rediscovery of the year. Personal politics aside, this is still a devastatingly effective warning of the consequences of communication failure and a timely reminder that it is our very ability to exchange, understand and accept ideas that are different to our own that prevents us from tipping back into barbarism. As a piece of film-making, it is consistently astonishing, using editing with an economy and purpose that is virtually without peer, at least at feature-film length. This is superb cinema, superb outsider cinema, and deserves to be widely seen and provoke as much angry, prejudice-laced debate as it can.

As for Eureka's disk, well I can't fault it – the transfer, given the film's 16mm origins, is excellent, the commentary and Watkins introduction are both fascinating, and the accompanying booklet crammed to the gills with information. Very highly recommended.

* The effect on this particular group of students was intensified by the fact that the nuclear strike depicted in this extract was taking place a mere four miles from where the lesson was being held.

** Joan Churchill is a key link between the ground-breaking work of direct cinema and the new wave of documentary features of recent years. Having cut her teeth as camera operator on the Maysles Brothers 1970 Gimme Shelter and co-photographed the vérité TV documentary series An American Family (1973), she later became a regular collaborator with British documentary film-maker Nick Broomfield, photographing and co-directing works with him, including Soldier Girls (1981) and Aileen: Life and Death of a Serial Killer (2003).