Postal interception

Postal interception is the act of retrieving another person's mail for the purpose of ensuring that the mail is not delivered to the recipient, or to spy on them.

For instance, the CIA and FBI were involved in numerous large-scale operations targeting U.S. activist groups, whose mail was opened and photographed. In one such programme, over 215,000 letters were opened. In the United Kingdom, the Special Investigations Unit of the General Post Office was responsible for postal interception.