"All you need is an individual with the desire - and the trigger - to switch into action." ... Gadi Aviran, Israeli intelligence consultant. In a discreet warehouse located on a farming commune 15 kilometres north of Tel Aviv, Aviran's company Terrogence employs a small army of cyber spies who infiltrate the password-protected internet chat rooms and online forums that are being frequented by would-be bombers who want to plot, plan and discuss potential attacks. Founded more than seven years ago, Aviran recruits mostly from the ranks of ex-military intelligence officers who can bundle the kind of expertise that is often too difficult for many of his clients to collect themselves. ''In the operations room here we have people who are fluent in Arabic, Farsi, Chinese, French, Spanish, Portuguese and English,'' Aviran says. ''We knock on the front door of these websites and chat rooms, we build trust, then we enter and start listening. As far as anyone else is concerned, we are them.''

Given the long list of well-paying clients who want to know exactly what is going on in the shadowy world of international terrorism, business is thriving. ''We are present in some fairly dark corners of the internet, monitoring, gathering information, watching discussions unfold in real time about how to plan attacks on mostly Western targets,'' he says. Gone are the days, Aviran says, when aspiring militants take themselves off to training camps to learn how to use violence to promote an extremist agenda. ''All you need is an individual with the desire - and the trigger - to switch into action,'' says Aviran. ''You can do it all yourself, without even leaving a footprint. Just walk into an internet cafe, download what you need onto a flash drive, load it into your home computer and start planning.''

Aviran calls on one of his operatives to demonstrate a discussion string picked up in the past weeks. The discussion was hosted from a web address in Yemen and included participants across the Arabian Sea in India and Pakistan. ''The original question focused on how to use easily available, dual-use materials to attack places such as shopping centres and movie theatres,'' the Terrogence operative says. In the course of the discussion, one participant suggested a device that could release cyanide gas into the atmosphere - as a means to create panic more than cause actual injury. Using a combination of cyanide salts and sulfuric acid in a powdered milk can, Aviran says the device could be an effective means of disrupting the social life of a large city. ''In this case the idea is to drop the device from the top floor of a shopping centre to the group floor,'' he says. ''Glass vials inside containing the sulfuric acid break open, the acid mixes with the salts and the gas is released. It might not kill, but it's real effect is fear.''

Aviran and his team pass on the recipes to a former Israeli army bomb technician and university-trained chemist, Avi Icar, who uses a research facility at Tel Aviv University to test the recipes. Icar not only specialises in building explosives, he also hand sews the clothing that could be used to hide bombs inside vests, jackets, pants, underwear and footwear. In any case, Icar warns, the authorities will soon be confronted by people trying to hide explosives not just in their clothes but inside body cavities or sewn beneath the skin. ''The quality of the information that is out there, the different ways to cut corners to produce the compound formulas needed to build an improvised device is sometimes astounding,'' Icar says. Sitting in an office adjacent to his university lab, Icar goes through a kitchen recipe for diazodinitrophenol, known as DDNP, a highly effective compound used as a detonator.

''Airport security officers are trained to look for more common substances used for detonators such as lead azide, so when DDNP passes through a scanning machine it's virtually impossible to detect.'' According to Aviran, the nightmare scenario remains the use of what he calls CBRN - a chemical, biological, radiological or nuclear device. ''We have followed discussion chains that track nuclear materials through hospitals, pinpointing exact locations. How long before someone steals that kind of material, attaches it to a bomb and detonates it, it's impossible to predict.''