High command of military's all-seeing eye

The hills of South Armagh not only have eyes, but also ears. In fact, for the last 16 years they have bristled with high-tech surveillance systems, such as infrared cameras, directional microphones capable of listening to conversations inside houses, and radio aerials to pick up any sort of transmission in the area known infamously as "Bandit Country".

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The hills of South Armagh not only have eyes, but also ears. In fact, for the past 16 years they have bristled with hi-tech surveillance systems such as infrared cameras, directional microphones capable of listening to conversations inside a house, and radio aerials to pick up any sort of transmission in the area known infamously as "bandit country".

The surveillance is carried out from inside a dozen or so "listening posts" ­ though the Army prefers to call them "hilltop locations", a euphemism which ignores the main task they carry out. As well as the equipment, each post has its own garrison with a small squad of soldiers, a helicopter landing pad and a bunker.

The purpose of the posts is to gather intelligence, although the Army refuses to say what type exactly, or how they do it. "We wouldn't want to discuss that sort of information," a spokeswoman said, "for operational security reasons".

But it is known that the posts contain a range of cameras which can monitor movements 24 hours a day.

They will include high-quality still cameras, such as the Nikon D1, the latest digital camera that can swiftly download pictures on to a computer. The technology installed in these towers will also include a computer system that contains details of suspected terrorists including their photographs and criminal records.

Paul Beaver, a military analyst, said the cameras would be used with a 500mm lens which could identify faces with high resolution pictures up to a kilometre away in good weather. A variety of television-style cameras would also be used for round-the-clock observation.

The latest second generation thermal imaging equipment, similar to the technology used for tank gunners, would also be part of the surveillance package. The technology gives the Army the capability of reading car number plates in the dark with the information from the images instantaneously sent across bases in Northern Ireland and back to the mainland. Further technology could be used to improve indistinct images.

The microphones are likely to have a range of between 500 and 1,000 metres and are aimed at points where suspected terrorist activity or planning are taking place. They can pick up a conversation on a street or even inside a house through the subtle movement of glass in a window.

The intelligence officers have access to a wide range of computer software, including voice recognition programmes, which can identify those having the conversation, Mr Beaver said they were also likely to have equipment capable of listening in on mobile telephone calls and similarly, any radio traffic is routinely monitored for useful information.

At night, helicopters fly with their lights off, using infrared systems for navigation to prevent paramilitaries from shooting at them.

Security chiefs argue that they must remain on a high state of alert because of the deadly threat posed by republican splinter groups.