Undercover policing

The inquiry was triggered by revelations from whistleblowers like Peter Francis and the investigative work of the Guardian, which exposed how undercover officers had assumed the identities of deceased children to infiltrate protest groups. These officers often spent years living as activists, with many entering into long-term, intimate sexual relationships with women who were entirely unaware of their partners' true identities—some even fathering children before disappearing.

The inquiry is divided into "tranches" based on time periods. In June 2023, the inquiry published its Tranche 1 Interim Report, covering the years 1968 to 1982. Sir John Mitting reached the landmark conclusion that the SDS was "not justified" and should have been disbanded in the 1970s. He famously stated that "the end did not justify the means," finding that the unit's contribution to public order was minimal compared to the massive intrusion into the private lives of citizens.

As of January 2026, the inquiry has moved into Tranche 3, focusing on the final years of the SDS (1993–2008). Very recent evidence (published early in 2026) has further exposed the deep collaboration between these undercover units and MI5, revealing that thousands of surveillance reports on peaceful campaigners were routinely sent to the Security Service. This "product" was used to build files on democratic activists, union members, and even children as young as 13.