Surveillance is covert if it’s done in a way that tries to ensure the subject is unaware it is, or could be, taking place. Covert surveillance is divided into two categories, both of which are subject to the Covert surveillance and property interference code of practice.
Directed surveillance operations involve the covert monitoring of targets' movements, conversations and other activities.
All of MI5's directed surveillance operations are subject to an internal authorisation system, which is required by Part II of the Regulation of Investigatory Powers Act 2000 (RIPA). These operations also run in line with the Covert surveillance and property interference code of practice.
This work is carried out by highly skilled specialist surveillance officers who may work in vehicles, on foot or from fixed observation posts. Our surveillance section often works in close co-operation with others, particularly the police.
Intrusive surveillance involves the covert monitoring of targets, using an eavesdropping device for example, on residential premises or within a private vehicle. Due to their invasive nature, our use of such methods is subject to a strict control and oversight regime.
To install an eavesdropping device in a target's home, for example, we need to apply to the Secretary of State (invariably the Home Secretary) for a warrant under Part II of the Regulation of Investigatory Powers Act 2000 (RIPA) to authorise the intrusion on the privacy of the target.
In most cases we must also apply for a "property warrant" under the Intelligence Services Act 1994 to authorise any interference with the target's property that is necessary to install the device covertly. As with interception, we must convince the Secretary of State that what we are proposing to do is both necessary and proportionate.
The rules for using surveillance techniques or interfering with property are explained in the Code of practice on covert surveillance. Unlike interception, the product from an eavesdropping attack can be used in court as evidence.
Our use of warrants authorising intrusive surveillance is monitored by the Intelligence Services Commissioner, who produces an annual report on his findings.