The Role of Intelligence in War

Since war began the role of intelligence has been vital. Knowing where your enemy is, what he is doing, with what and what he is capable of, has always been a huge advantage.  Intelligence can be classified into three main categories;


Information relating to that particular local area or engagement, for example who exactly is guarding a particular bridge or strongpoint, is there a tank or other armoured assets in the area, or the strength of a particular unit in the area.


Information relating to a particular battle or campaign, units, strengths, whether a particular bridge is intact or a river crossing possible, location of enemy supply trains and depots. Such tactical intelligence became very important during the Napoleonic Wars and was one of Napoleons strengths when using his Corps system. In medieval times such as at the Japanese battle of Sekigahara and the English Battle of Bosworth it could be about which side a particular Noble was actually going to fight for, as this could change during the course of a battle. This kind of intelligence is vital in naval warfare as knowing where the enemy fleet is can determine the course of a battle as at the Battle of Midway.

Strategic Intelligence;

Strategic intelligence is of a yet bigger scale. This relates to a whole theatre of war or a country, its intentions and capabilities. In the modern era this may not just be related to military power but also economic power or intelligence relating to specific resources such as oil, minerals and even in the 21st century access to bio fuels. During the Cold War this was focused on the ability to make and the number of Nuclear weapons.

Intelligence is of great importance but good quality intelligence can often be hard to come by. Historical intelligence may have been hard to gather, even if money was available for bribes, infiltrating a foreign country which may have different language and culture is always difficult. In the modern era acquiring intelligence isn’t the problem, in fact quite the opposite - it can be sorting what intelligence is actually relevant or accurate from a huge amount a data, this is sometimes called sorting the “Signal from the noise”. In the modern era there is a vast amount of open intelligence, which is available from newspapers, TV, media and even the internet, whereas the traditional need for covert intelligence (things your enemy doesn’t want you to know) still remains.

Sources of Intelligence

Intelligence can be further classified by its source

Human intelligence (HUMINT)

Human intelligence is the oldest method and indeed is often referred to as one of the oldest professions. This is gathered by informants and agents - the traditional spies.  Intelligence gathered in this way could be in the form of documents which have been copied or stolen, or information passed on in person. For those conducting such intelligence gathering the risks can be high, during wartime most countries execute foreign spies who have been caught often after a period of torture.  This form of intelligence gathering has been popularized by film and TV characters such as James Bond but is often much less glamorous with some human intelligence being just a case of someone keeping their eyes open while in another country. It can be a very sleazy world with blackmail and the use of sex common as demonstrated by the East German spy master Markus Wolfe. With the chance of betrayal and the risk of double or even triple agents the reliability of such intelligence is often questionable. Its use against tightly knit terrorist groups such as Al Qaeda is also very limited as infiltration is extremely dangerous and difficult.

Photographic and Satellite Intelligence (PHOINT and SATINT)

With the advent of aerial photography during the First World War the use of photographs to provide accurate overviews of a battlefield, troops on the move and resources such as factories and bridges became increasingly important.  By World War two specialised photo reconnaissance aircraft (such as the Lockheed Lightning or de Havilland Mosquito) were coming into service, often adapted versions of fighter or light attack aircraft which had the speed to avoid pursuit and return safely with their precious photos. Again this source of intelligence is far from perfect as Operation Market Garden showed and counter measures such as fake units used in the preparation of the D-Day landings could easily fool photos from the air.

As the Cold War developed a new breed of photo reconnaissance air craft developed, which were unarmed but used either high speed (such as the SR-71 Blackbird and the recon version of the MiG-25 Foxbat) or very high altitude (U-2 spy plane) to avoid being shot down. Such aircraft would fly very near an enemy border (if not covertly over it) and take pictures from high altitude. As it became too politically sensitive to over fly a rival county’s air space and surface to air missiles developed in size and speed much of this role was overtaken by the use of satellites. Advances in thermal imaging and photography have improved the usefulness of such intelligence.

An advantage is that as an intelligence resource satellites are fairly safe although hunter killer satellites do exist, as well as far less costly anti satellite missiles which can be ground or air launched.  A disadvantage is that it can take time for a satellite to come round on its orbit so information can be dated and it can also take time and use up fuel which reduces a satellites service life to move it to a different orbit to cover a different area.  Battlefield reconnaissance is now often carried out by remotely piloted vehicles or RPV’s/ Such technology has advanced greatly in recent years and allows easily deployable assets which can over-fly dangerous areas without risking a human pilot.

Electronic and Signals Intelligence (ELINT and SIGINT)

This is collection of data from the interception of not just radio signals but any kind of electronic data. Modern technology can ‘leak’ information which can be picked up by specialist equipment. As mentioned before the sheer volume of data collected can be staggering.  Such collection of intelligence started with the arrival of wireless and radio technology and developed during World War Two. Also among this kind of intelligence is what is known as ‘Traffic analysis”  - this is where the amount rather than the content of radio transmissions is analysed to give clues about troop or ship movements.  Mobile phones have become an integral part of modern western society and have been used by terrorist cells to communicate, posing new challenges to the security and intelligence services and increasing further the volume of data which can be intercepted. Most large countries have specialist organisations devoted to the gathering and analysis of such information such as the Government Communications Headquarters (GCHQ) in the UK which evolved out of the Second World War code breakers at Bletchley Park

One thing is certain - the role of intelligence gathering continues to be of utmost importance not only in wartime but in modern counterterrorism operations. The old problems of the validity of the information received remains, now coupled with the huge volume of data that can be received.
Intelligence in War: Knowledge of the Enemy from Napoleon to Al-Qaeda, John Keegan. A detailed and wide ranging look at the role of intelligence in warfare covering a big historical period from Napoleon to the present day. It offers many interesting insights but is slightly weaker on post World War two aspects. A recommended read by one of the worlds leading military historians. [see more]
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Silent Warfare: Understanding the World of Intelligence, Abram N. Shulsky, Gary J. Schmitt and Gary Schmitt. A superb introduction to the subject, well written and engaging and useful for the casual reader who wants to know more behind the headlines and as an introduction text for students. Covers all major subjects in the area and many of the frequently used technically terms. Highly recommended.
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Intelligence and Statecraft: The Use and Limits of Intelligence in International Society, Peter Jackson and Jennifer Siegel. A book for the serious student of the theory of intelligence, the book is very up to date and looks at the results of the Hutton enquiry and the Post 9/11 US enquires. It seeks to put intelligence gathering and its use in International Relations into a historical context and claims that in many ways the methods used to gather intelligence and the use it is put to have changed little since Roman times.
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How to cite this article: Dugdale-Pointon, T. (22 August 2007), The Role of Intelligence in War,

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