By Gavin Knight
They can fly, they can swim, they can spit out 550 high-explosive shells a minute. And most terrifyingly of all, they'll soon be able to think for themselves
A few minutes before nine in the morning, and the young soldiers have no idea of the horror that is about to strike them. They are taking part in a massive military training exercise, involving 5,000 troops, and are about to showcase the latest in robotic weapons technology.
The MK5 anti-aircraft system, with two huge 35mm cannons, is essentially a vast robotic weapon, controlled by a computer.
Killing machine: The SWORD is mounted with either an M240 machine-gun, a grenade or rocket launcher
But while it's one thing when your laptop freezes up, it's quite another when it is controlling an auto-loading magazine containing 500 high-explosive rounds.
As the display begins, the South African troops sense quickly that something is terribly wrong. The system appears to jam - but what happens next is truly chilling.
'There was nowhere to hide,' one witness stated in a report. 'The rogue gun began firing wildly, spraying high explosive shells at a rate of 550 a minute, swinging around through 360 degrees like a high-pressure hose.'
One young female officer rushes forward to try to shut down the robotic gun - but it is too late.
'She couldn't, because the computer gremlin had taken over,' the witness later said.
The rounds from the automated gun rip into her and she collapses to the ground. By the time the robot has emptied its magazine, nine soldiers lie dead (including the woman officer).
Another 14 are seriously injured. The report will later blame the bloodbath on a 'software glitch'.
It sounds like a blood-spattered scene from the new blockbuster Terminator Salvation, in which a military computer takes over the world using an army of robot soldiers.
But this bloodbath actually happened. And concern is mounting that it may happen again and again, as a growing number of military robots flood the battlefield.
Saving lives: The Talon is used primarily for bomb disposal
Indeed, Pentagon insider Peter Singer believes that we are witnessing the dawn of the robot warrior age.
'Just look at the numbers,' he says. 'We went into Iraq in 2003 with zero robots. Now we have 12,000 on the ground. They come in all shapes and sizes, from tiny machines to robots bigger than an 18-wheeler truck.
There are ones that fit on my little finger and ones with the wingspan of a football field.'
The U.S. military is the biggest investor in robot soldiers. Its robot programme, dubbed Future Combat Systems, is budgeted to spend $240 billion over the next 20 years.
But Singer is worried that in the rush to bring out ever more advanced systems, many lethal robots will be rolled out before they are ready.
It is a terrifying prospect. 'Imagine a laptop armed with an M16 machine-gun,' one expert said.
According to Noel Sharkey, a professor of robotics and artificial intelligence at Sheffield University, one of the biggest concerns is that this growing army of robots could stray out of communication range.
'Just imagine a rogue robot roaming off the battlefield and into a nearby village,' he says. 'Without experts to shut it down, the results could be catastrophic.'
One of the most common, and fastest, military robots in service is the Talon. Weighing just 52kg, it has one long, mobile arm and is used primarily for bomb disposal.
It can move through snow, sand and water.
Auto-pilot: A robot bomber patrols the skies
There are 2,500 of these robots in Iraq and if they are damaged, they are flown to one of six dedicated 'robot hospitals' for repairs.
They are then returned to combat within hours.
The Talon is unarmed, but can be disturbingly temperamental. Singer gives a worrying example of one sergeant just back from Iraq who described how his Talon robot acted 'erratically'.
Another told how his robot would 'drive off the road, come back at you, spin around, stuff like that'.
I spoke to one soldier in the U.S. Army's 3rd Infantry division, stationed at Forward Operating base Kalsu, 20 miles south of Baghdad, who works with Talons.
'They all have different personalities,' he says. 'The way they move, the way the arm doesn't move like it's supposed to. You have to learn their quirks.'
Which is fine - until it is also lethally armed.
A deadlier version of the Talon is the SWORD - and this is a killing machine. The SWORD is essentially a Talon robot mounted with either an M240 machine-gun, a grenade or rocket launcher.
Boasting this kind of firepower, stories about 'quirks' and ' personalities' become far more alarming.
In his new book, Wired For War, Singer tells how a roboticist at a rival firm told of an incident in testing where a SWORD had spun around in circles, as if drunk.
The Marines Corps' Gladiator combat robot prototype, which is the size of a golf cart and heavily armed, had similar problems when tested, driving about in a circle that left those at the exercise not knowing 'whether to laugh or run away'.
The SWORD is also a keen marksman. It can shoot an apple from hundreds of metres using a machinegun with the accuracy of a sniper rifle. That is an incredible capability.
But it can't tell the difference between an apple and a tomato. This is a major cause for concern for many experts. If it can't tell an apple from a tomato, they ask, how can it tell the difference between an insurgent and an innocent child?
A spokesman at Qinetiq, which manufactures SWORD, denies the product's disturbing glitches, dismissing them as 'completely unsubstantiated'.
But even Qinetiq can't keep track of all their units once they are in service. 'Once those units are sold, we can't comment as they are with operational forces,' said a spokesman for the company.
Hoverbot: The Pentagon is creating the Wasp - a radio-controlled device similar to the one pictured that can be used literally as a fly on the wall
'It would be like Ford trying to track all its cars.'
Qinetiq also emphasises, however, that its robots are 'saving lives every day in Iraq'. Indeed, Qinetiq is forging ahead with a whole array of new military robots, including a lightweight, solar-powered spy plane which can remain airborne for months.
But Singer also has the inside track on the Pentagon's plans for robot warfare. As well as working in America's military HQ, he coordinated Barack Obama's defence policy during his presidential campaign.
'There are various humanoid military robots in the pipeline,' he says. 'Some of the military's ideas are straight out of science fiction.'
In the forthcoming blockbuster Terminator Salvation, which is out on June 3, we are presented with a nightmarish scenario in which armies of machines roam a post apocalyptic landscape, destroying any remnants of human civilisation.
Huge 'Harvesters' hunt down humans en masse, while brutal, humanoid 'Terminators' round up the survivors.
The bedraggled human resistance, whose leader is a character played by Christian Bale, even encounters vicious underwater robots which patrol the oceans.
Disturbingly, these terrifying creations are now inspiring the latest real-life innovations.
'One member of the military so liked the look of the Terminators that he asked the Pentagon to build one,' Singer says.
'There is nothing unusual in this. After all, the idea for the mobile phone came from Star Trek, while the tank was created after Winston Churchill read the science fiction of H.G. Wells.'
But the greatest fears concern what will happen when increasingly advanced military robots become 'autonomous' - that is, able to make their own decisions.
At present, most robot soldiers are operated by a human who controls their every move. But there are advanced plans to let robots fight on their own.
Indeed, one U.S. military proposal clearly states: 'Fully autonomous engagement without human intervention should be considered - both lethal and non-lethal.'
One of the world's leading roboticists, university professor Ron Arkin, who works with the Pentagon's technology arm, confirms that the Future Combat Systems programme is fast moving towards such autonomous systems.
'I envision them being used in allout war, for example,' he said. 'Ten to 20 years from now, robot warfare could be a very different story.'
This raises a whole new range of problems. Professor Sharkey, for example, claims the Pentagon is developing 'Multi-Robot Pursuit Systems' which will be used for house clearance.
They will pursue people like a pack of wolves,' he said. 'But if you have several people running away, how will the robots decide who to shoot? A lot of innocent people will die.'
And what happens if terrorists get hold of the technology?
'These military robots are simply programmed to detect and shoot,' says Prof Sharkey. 'They are stupid, dumb. They don't ask questions and the hit rates are incredible.
'It would be easy for anyone to set one up on a rooftop and leave it to shoot an innocent crowd to pieces.'
The manufacturers admit that their robots could fall into enemy hands, but say that this is a risk with any conventional military weapon.
Robots, however, are harder to destroy, don't feel fear and can't be interrogated if they are captured. In short, they can be used with far more devastating results.
'We already know that in the Middle East, Hamas is using remote controlled planes,' says Prof Sharkey.
'I can go on the internet today, buy a plane about 2ft long which cannot be detected by radar, connect it to a mobile phone and use the phone to guide it.'
Forty-three countries are developing military robot programmes, including Russia and China. And it is fast becoming an arms race.
Past, present and future? Christian Bale, left, takes his anger out on a robot from new film, Terminator Salvation, while Arnie, right, shows what he's made of in Terminator 3
The Pentagon's technology wing is determined to stay ahead in the game - and is creating ever more bizarre devices.
There is the Wasp, a radio-controlled flying insect that weighs just 170g and can be used, quite literally, as a fly on the wall.
Then there is the Cormorant, a sea launched robot which can swim to a depth of 150ft, and the PANDA, which stands for Predictive Analysis for Naval Deployment Activities, and which helps track down Somali pirates.
One new sentry robot, with a built in 5mm light machine-gun, patrols the demilitarised zone between North and South Korea.
The SGRA1 is made by Samsung Techwin and can pinpoint targets at up to 500m using a colour camera. Israel has introduced armed robotic sentries in pillboxes along the Gaza border.
'This is amazing technology,' says Singer, 'but it raises disturbing, fascinating questions. On one hand, hundreds of soldiers are alive today thanks to robots.
'The flip side, however, is that they allow us to use more force with less risk. Eleven out of the top 20 Taliban leaders have been killed by robot drones.
'But how many innocent people have been killed in the process?'
Either way, military robot technology is advancing at an alarming pace. 'We are experimenting to see whether we can embed the laws of war and the rules of engagement into an autonomous robot soldier.
'Our initial results are promising and I believe it is possible to constrain a robot's behaviour to a moral code.'
But the impetus to create a fully-functional, fully-autonomous robot warrior is a political one.
'Body bags containing real soldiers coming home affect the government electorally,' says Sharkey. 'Once you start using robots, you remove this problem.'
But do we really want going to war to be as easy, and impersonal, as playing a computer game?