SET REPORT / Here comes a chopper: The feminist fantasy Small Metal Jacket puts nuns on the run in 'Nam. James Rampton visits the scene

A monstrous American Huey combat helicopter - one of those famous for blaring out Wagner in Apocalypse Now - has landed on a clearing in a lush tropical jungle. With the blades still clattering overhead and throwing up leaves and smoke, a group of American women soldiers disguised as Buddhist nuns in striking orange headgear and robes leap from the helicopter and begin to unload crates of supplies marked 'Chainsaws', 'Astronaut Food', 'Champagne', 'Smoked Oysters', 'Pagoda', 'Party Items' and 'Body Bags'.

We are not in Saigon or My Lai, but sleepy Bray, near the Waterside Inn, one of the country's most luxurious restaurants, deep in the stockbroker belt of affluent Royal Berkshire; there is a part of England that is forever Vietnam.

The soundstage at Bray Studios, formerly home to Thunderbirds, Stingray, and Dracula - Prince of Darkness, has been occupied by its largest set for 10 years: a massive and meticulous re-creation of a South-east Asian jungle. (Hundreds of South-east Asian pot plants were hired from a company specialising in greening office atriums. Unfortunately, a thousand-pound banana tree was decapitated by a model helicopter in a long shot). And it is all for the purposes of filming a new BBC 'ScreenPlay', Small Metal Jacket, an adaptation of Emily Prager's feminist black comedy.

'The last thing anyone wants is another Vietnam movie,' concedes the scriptwriter, Scott Roberts, who cut his teeth on The American Way with Dennis Hopper. 'But this is not really about Vietnam; it's just a very specific situation reflecting an incredibly important universal theme - that women are always vulnerable.'

They combat vulnerability in this drama by means of a contraption the very thought of which is designed to make men squirm. The Lincoln-Pruitt Anti-Rape Device - or 'Leopard' - is worn internally by a band of female American GIs, under the formidable command of Major Lincoln-Pruitt. Controlling the retractable, deadly poisonous spikes of the device with their pubococcyneal muscles, the soldiers of the 'Foxy Fire' platoon are using it to avenge themselves on the Vietcong - if not the whole of male-kind. (They land in Vietnam dressed as Buddhist nuns because they know that they are far more likely to be raped wearing habits.) It is the sort of image Picasso might also have had in mind in the vagina dentata evident in his female nudes.

Lincoln-Pruitt (played by the American actress Debora Weston) outlines her plan: 'We've been destroying men since Eden. How? Through sex.' When she demonstrates the efficacy of her device by inserting a broom-handle into it and reducing it to sawdust, this male viewer found himself involuntarily crossing his legs. 'It is enough for men to think that it could exist,' smiles the producer Caroline Oulton, whose idea it was to bring Prager's fantasy to the screen.

The subject-matter is certainly near the knuckle (as well as other parts of the body); it is the sort of film that could fill several mailbags to Points of View. Roberts rather edgily confirms that 'there were some worries in the BBC hierarchy about 'the tone.'

'But it's going to be tasteful,' he continues hastily. 'You won't see any gynaecological implements like in David Cronenberg's Dead Ringers or flies on rotting bodies, and there won't be as much naked female flesh as the boys would like. It's never going to be Playboy Channel material, although it is overtly erotic.' It is true that the seduction scenes have the allure of watching a Venus fly-trap in action.

Roberts also hopes that the potentially strident feminism of Small Metal Jacket is leavened by a sense of humour. 'If it wasn't immediately set up as a black comedy, it could be dodgy politically,' admits Weston, taking a breather from lugging boxes of body-bags. The aim is 'to make it funny,' Oulton asserts. 'It is difficult to make a comedy about serial murder, but once you stick in nuns in immaculate make-up, a cartoon element inevitably creeps in. The one problem is that sisterly sado-masochism is not exactly an English skill.'

No, but at least it gives the play originality; even in the wildest dreams of a conspiracy-theorist 'reds under the bed' back-bencher, the BBC does not make that many comedies about sisterly sado-masochism. It is as cheap as it is cheerful. Small Metal Jacket recreates the Vietnam War on a budget of pounds 300,000 - 'less than they spend setting up the average hair commercial', according to Roberts. Oulton moans that she had to cut two speaking parts (more expensive under Equity rules) to pay for a tutor to teach the actresses how to say 'My, what a beautiful big penis you have' in perfect Vietnamese.

Vietnam is a familiar battlefield, and veteran viewers, who have seen the country used as a setting for everything from adverts to comedy sketches, demand high standards of accuracy. Hence the preponderance of 'Namstalgic cliches - acid, Hendrix, The Doors, the 'thousand-mile stare', grunts wearing badges proclaiming 'Enjoy Co-Caine' and 'Question Authority', and enough joints to wreath the jungle in a permanent smokescreen. The props man, Dominic Smithers, had to track down the only Huey helicopter in Europe (captured from the Argentinians during the Falklands War).

Smithers crows that Stanley Kubrick, maker of the more famous Full Metal Jacket (the only other 'Nam-pic shot in Britain), got many of his period details wrong. 'They used Westland instead of Huey helicopters - it's not a favourite film of helicopter spotters.'

Despite the Huey, it is not at all certain that the helicopter-spotting fraternity will like Small Metal Jacket, either.

'Small Metal Jacket' will be broadcast in a double bill with 'Dread Poets' Society' at 9pm Wednesday, BBC2.

(Photograph omitted)