CHARLIE One offers an insight into the activities and tactics of the British intelligence agencies operating in the north.
It also provides a glimpse into some of the technology available to snoops and spooks locked in a potentially deadly battle with republican paramilitary groups.
In that hidden war information is king and in his book Seán Hartnett reveals the lengths British intelligence agencies are willing to go to keep tabs on their enemies.
From cars and motorbikes kitted out with hidden cameras to high-powered bugs the size of a lighter, the equipment used by the Joint Communications Unit - Northern Ireland is worthy of any spook thriller.
Installing “search gear” in cars that could track weapons, vehicles and people in real time were all part of Hartnett’s daily workload, while installing communication equipment, hidden microphones and gear stick mounted microphone switches is the stuff of any James Bond fantasy.
While the range of surveillance methods used by the British will come as no surprise to some, Hartnett’s detailed description of his unit’s modus operandi provides a unique glimpse into the shadowy surveillance world of British intelligence.
He reveals how the British use mobile phone GSM technology on spying missions to transmit signals via the phone network.
He also casts a light on the stealth tactics used to steal cars owned by suspects in order to place trackers and bugs in them before returning the vehicle.
The ability of his unit to jam radio frequencies used by CCTV cameras in order to gain access to target buildings unnoticed is also highlighted.
He revealed that several Special Communications Troop units attached to the Joint Communications Unit – Northern Ireland which are based at RAF Aldergrove cover parts of Fermanagh, Down and south Antrim.
One of those units, SCT 7, is responsible for producing cameras hidden in rocks and trees that can then be deployed against targets.
Hartnett also revealed that his unit used a series of overt and covert cameras, some with the capability of reading a number plate up to 1.8 kilometres away.
He says the cameras uses a vast network of encrypted fibre optic cables have been installed across the north for the “exclusive use of British intelligence”.