When machines turn mean

MEET Nestor Class 5, the world's fully automated domestic assistant. This state-of-the-art robot is the shape of things to come in the not-too-distant future, 2035. This mechanical marvel, claims the makers, is "ready to do what you want, when you want".

The NS-5 has over 456 moving parts, three pounds of processing circuitry, two miniature nitrogen cooling tanks and almost one mile of aluminium wiring. Its 35,000-plus programmes includes 300 recipe/ingredient lists, automated laundry capability (including fluff'n'fold), accounting and tax software, and dog grooming protocol.

All this sounds too good to be true - which, of course, it is. NS-5s are the heart of the blockbuster sci-fi thriller I, Robot based on Isaac Asimov's novels and, obeying the rule that robots can turn nasty, they're soon refusing to take orders and over-riding their instructions.

In other words, these mechanical creatures are no different to most other cinematic machines.

Robots, androids, cyborgs and replicants come in all shapes and sizes. They can protect, they can cook, they can clean, they can be programmed to do pretty much anything you want - up to a point. Just like computers, they break down through malfunction, a virus or bad programming. The servant wants to be the master and has the circuitry to get his own way.

Man's relationship with metal men and women has been an uneasy one on screen since the silent movies. The vision of the future - the 21st century - in the first robot movie, Metropolis, in 1927 was a beautiful one. She was Maria, a sleek, metallic, art deco female robot in a city where everything was done by enormous machines run by an army of slave workers. Predictably, it all ended in tears with union leader Maria leading a slave rebellion. Ever since, movie-makers have been borrowing futuristic ideas and images from Fritz Lang's film.

Our love-hate relationship with machines stems from our desire to have the best of both worlds, desiring someone - or something - to do all the jobs we find tedious, boring or messy, but asking nothing in return apart from the occasional software update.

Nothing has been learnt from past cinematic mistakes as robots have become too big for their metallic boots, preferring to be in charge rather than servile assistants.

But not all robots are unruly. A few mechanical men are benign, like Tinman in The Wizard Of Oz, while droids R2-D2 and C3-PO in the Star Wars saga were as cute and cuddly as lumps of metal and wire can be. The lovable trio of Huey, Dewey and Louis, robotic helpers in a garden of Eden spaceship in Silent Running, were willing to sacrifice themselves for the sake of their mission. This proved one of the few occasions when audiences shed a tear over the fate of a robot, even if there was nothing technological about them as they were played by young amputees walking on their hands.

Johnny Five, from Short Circuit and its sequel, turned from mean machine to metal hero after being struck by lightning. Audiences found his acting more convincing than his flesh-and-blood co-stars.

Comic robots are rare, although Woody Allen's Sleeper raised laughs with the prospect of Orgasmatron booths to replace sex.

Robby the robot in Forbidden Planet, a 1956 sci-fi adventure fashioned from Shakespeare's The Tempest, was described as looking like a cross between a jukebox and the Michelin Man. His human characteristics and sense of humour helped him become an icon among cinematic metal men.

The 8ft alien robot Gort was imposing standing guard over the space invaders flying saucer in The Day The Earth Stood Still. In reality, he was a very tall doorman spotted by director Robert Wise.

With some androids, such as Arnold Schwarzenegger's Terminator, his bark is worse than his bite. He looks mean and awesome but deep down is a metallic pussycat. The T-man's mission was to protect not destroy, although violence and mayhem in self-defence was permissible.

The Terminator, who was updated for each sequel, represented an advance that took advantage of progress in computer science. He was not only intelligent, able to walk, talk and fire a gun, but could learn from past experience. He was flesh and blood on the outside, a sophisticated computer inside.

But when robots are bad, they are very bad indeed. Director Stanley Kubrick gave the spacecraft computer a name - HAL - in 2001: A Space Odyssey and a personality that made it try to take over the astronaut's mission. He's only one in a long line of megalomaniac machines.

Sometimes a robot will looking eerily human. Yul Brynner played a theme park robot gunslinger in Westworld, looking exactly like the man in black he played in The Magnificent Seven. Officer Alex J Murphy metamorphosed into Robocop, a lawman whose methods of capture were borrowed from Dirty Harry.

Spare-part surgery led to the creation of The Mark 13 in low budget Brit horror flick Hardware. A head was presented to the hero's scrap metal sculpturing girlfriend and the murderous Mark 13 was born. His good deed was drilling out the eyes of a Peeping Tom.

Android love is taboo unless you're an expert like Jude Law's gigolo in Steven Speilberg's AI: Artificial Intelligence. He was a genuine love machine whose chat-up line was "Once you've had a robot lover, you'll never want a real man again".

Others don't know how to behave around women. Hector in Saturn 3, scripted by Martin Amis, took a shine to space station visitor and ex-Charlie's Angel Farrah Fawcett. She didn't fancy him or his maker, Harvey Keitel, but neither would take no for an answer.

Some robots are more animals than others. Runaway introduced the world to spider-bots, defective robo-creepy crawlies programmed to kill by mad scientist Gene Simmons (lead singer of Kiss). Mechagodzilla looked like he'd stepped straight out of a junkyard although his array of tricks - flame-throwing, missile-firing, laser-projecting - were impressive in Godzilla vs Mechagodzilla.

All this trouble doesn't stop humans exploiting machines and trying to make them more human. The new version of The Stepford Wives, in which female partners are transformed into robotic super-slaves by their husbands, went on release in cinemas last week.

The ultimate robo-servant was probably Andrew Martin in Bicentennial Man, based on work by sci-fi writer Isaac Asimov and Robert Silverberg. He served one family over four generations and eventually had himself reconstructed as a human so he could be with his true love.

Played by Robin Williams, Martin was so cloying and cute that you longed to pull out the plug. This is something that the humans in I, Robot should have done before the inevitable robot revolution.

* I, Robot (12A) opens in cinemas on Thursday. The Stepford Wives (12A) is on release now.

* Steve Pratt interviews Will Smith in 7DAYS in Thursday's Northern Echo.