At the beginning of the Troubles, intelligence was so poor that the Army rounded up for internment many innocent people, based on inaccurate or old information, in an act that backfired severely. But the security forces have learnt lessons which have made them one of the most formidable intelligence forces in the world. In recent years, there has been so much electronic surveillance, videoing, telephone tapping and bugging that it is a wonder that the Northern Ireland population does not glow in the dark.
Such spying has not been the sole preserve of the British state despite the vast resources it can bring to bear. As early as the 1970s, the IRA cannibalised television sets for their UHF/VHF receivers so they could listen in to Army radio communications.
In every area it has been a game of cat and mouse. When the IRA started using radio-controlled bombs, scientists at Britain's GCHQ listening post designed special radios to soak the province with signals. It was not until a number of Provisional volunteers had been killed by bombs that exploded prematurely that the IRA realised what was going on.
The IRA then switched tack and designed bombs that required two separate coded signals to detonate. GCHQ took a while to work this one out but eventually they did, and a few more IRA volunteers died.
In the last 20 years British intelligence has designed computer programs that keep huge amounts of personal data on a large section of Northern Ireland's population. These systems are said to store everything from their subjects' political and paramilitary associations to the colour of their wallpaper and the frequency of their car journeys.
In many ways, Northern Ireland became a testing ground for cutting-edge intelligence operations. Bugging is nothing new - only three months ago The Independent revealed that for a decade a tower near Capenhurst, Cheshire, was used by GCHQ to intercept telephone traffic in the Irish Republic.
In May last year Mo Mowlam was accused of compromising a bugging operation on the home in Belfast of Gerry Kelly, a leading Sinn Fein official and former IRA bomber. The house was used during "talks about talks" after the first IRA ceasefire. It is said that a false rafter was found in the living area of his house; it had been hollowed out and packed full of electronics which were used to monitor events for three years.
The equipment found in Sinn Fein's Ford Mondeo yesterday was clearly state-of-the-art equipment and British intelligence must be cursing to have had such an important piece of kit and an innovative modus operandi discovered.