Covert surveillance

What is covert surveillance?

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. It is divided into two categories, both of which are subject to the Covert surveillance and property interference code of practice. 

Directed surveillance 

Directed surveillance involves the covert monitoring of someone’s movements, conversations and other activities. 

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 cooperation with others, particularly the police. 

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. 

Intrusive surveillance 

Intrusive surveillance involves the covert monitoring of someone in their home or vehicle, using an eavesdropping device, for example. Due to their invasive nature, our use of such methods is subject to strict control and oversight. 

To install an eavesdropping device in someone’s home, for example, we need to apply to the Secretary of State (usually the Home Secretary) for a warrant under Part II of the Regulation of Investigatory Powers Act 2000 (RIPA) to allow us to intrude on their privacy. 

In most cases we must also apply for a "property warrant" under the Intelligence Services Act 1994. This authorises any interference necessary to install the device covertly in the target’s home. 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, intelligence gathered from eavesdropping or other forms of surveillance can be used as evidence in court. 

Our use of warrants authorising intrusive surveillance is monitored by the Investigatory Powers Commissioner's Office, which produces an annual report on its findings.