In Security Service terminology an 'agent' is a human source working within or close to a target organisation, who provides intelligence in secret to the Service. Agents are not members of the Service.
Agents represent one of the most important sources of secret intelligence.
Agent operations are run by specially trained officers and can last for long periods, sometimes for many years. Management arrangements for agent operations are also designed to make sure that the case is kept under proper control, drawing on advice from the Service's legal advisers as necessary. For instance, a key objective is to avoid placing the agent in the role of agent provocateur , by enticing those on whom he or she is reporting to commit criminal acts which they would not otherwise have committed. The Service pays close attention to the personal welfare of its agents, both during their agent career and after their active work for the Service has ended.