Clandestine human intelligence

Clandestine human intelligence is intelligence collected from human sources using clandestine espionage methods. These sources consist of people working in a variety of roles within the intelligence community. Examples include the quintessential spy (known by professionals as an asset or agent), who collects intelligence; couriers and related personnel, who handle an intelligence organization's (ideally) secure communications; and support personnel, such as access agents, who may arrange the contact between the potential spy and the case officer who recruits them. The recruiter and supervising agent may not necessarily be the same individual. Large espionage networks may be composed of multiple levels of spies, support personnel, and supervisors. Espionage networks are typically organized as a cell system, in which each clandestine operator knows only the people in his own cell, perhaps the external case officer, and an emergency method (which may not necessarily involve another person) to contact higher levels if the case officer or cell leader is captured, but has no knowledge of people in other cells. This cellular organization is a form of compartmentalisation, which is an important tactic for controlling access to information, used in order to diminish the risk of discovery of the network or the release of sensitive information.

Espionage is the act of obtaining (typically via covert methods) information that an adversary would not want the entity conducting the espionage to have. Espionage is inherently clandestine, and the legitimate holder of the information may change plans or take other countermeasures once it is known that the information is in unauthorized hands. See the articles Clandestine HUMINT operational techniques and Clandestine HUMINT asset recruiting for discussions of the "tradecraft" used to collect this information.

HUMINT is in a constant battle with counterintelligence, and the relationship can become very blurry, as one side tries to "turn" agents of the other into reporting to the other side. Recruiters can run false flag operations, where a citizen of country A believes they are providing intelligence to country B when they are actually providing it to country C.

Unlike other forms of intelligence collection disciplines, espionage usually involves accessing the place where the desired information is stored, or accessing the people who know the information and will divulge it through some kind of subterfuge. There are exceptions to physical meetings, such as the Oslo Report, or the insistence of Robert Hanssen in never meeting the people to whom he was selling information.

This article does not cover military units that penetrate deep between enemy lines, but generally in uniform, to conduct special reconnaissance. Such military units can be on the border of the line, in international law, which defines them as spies, if they conduct information in civilian clothes. In some circumstances, the uniformed personnel may act in support to the actual agents, providing communications, transportation, financial, and other support. Yet another discipline is covert operations, where personnel, uniformed or not, may conduct raids, sabotage, assassinations, propaganda (i.e., Psychological warfare), etc.