Mark Kennedy (born 7 July 1969),^[1] undercover name Mark Stone, is a former London Metropolitan Police officer who, whilst attached to the police service's National Public Order Intelligence Unit,^[2] (NPOIU) infiltrated many protest groups between 2003 and 2010 before he was unmasked by political activists as an undercover policeman^[3] on 21 October 2010^[4] and his identity was confirmed by the media three days later.^[5] During his time under cover he manipulated and deceived several women into having sexual relationships with him with the knowledge of his superiors. An Investigatory Powers Tribunal found his actions to be an "abuse of the highest order" and had "grossly debased, degraded and humiliated" one of his victims.^[6][7]

Kennedy was born in Camberwell, South London, on 7 July 1969, joined the Metropolitan Police around 1994 and served with them until March 2010. He was revealed to be a police infiltrator of protest groups on 21 October 2010.^[4]

In January 2011, it was reported that Kennedy was one of the first officers to work as an undercover infiltrator for the National Public Order Intelligence Unit and had spent seven years within the environmental protest movement.^[8]

In a Channel 4 interview broadcast on 14 November 2011, Kennedy stated that, in the guise of an environmental activist, he was used by the police forces of 22 countries. He also claimed he was instrumental in the closing down the original Youth House community centre in Copenhagen.^[9]

Kennedy said he was hired by German police between 2004 and 2009 and allegedly committed two crimes on their behalf, one of which was arson.^[9] German MP Andrej Hunko raised questions in the German Bundestag concerning what the German authorities knew about Kennedy's activities amongst the Berlin protest movement. Kennedy had been arrested in Berlin for attempted arson but was never brought to trial. Hunko also asked: "How does the federal government justify the fact that [Mark Kennedy], as part of his operation in Germany, did not only initiate long-term meaningful friendships but also sexual relationships, clearly under false pretenses?" The federal government refused to answer all questions relating to Kennedy.^[10]

Kennedy was involved in several environmentalist campaigns in Ireland, such as Shell to Sea. He allegedly encouraged protestors to attack police during the May Day 2004 protests in Dublin.^[11]

In February 2010, while still serving as a police officer, he set up Tokra Ltd, a private company at the same address as a security firm that works for the energy company E.ON, the owners of Ratcliffe-on-Soar Power Station. Later in 2010, he set up Black Star High Access Ltd, based in east London.^[1]

He manipulated several women into having sexual relationships with him, with the knowledge of his superiors.^[7]

Kennedy said in an interview, arranged through his PR agent Max Clifford,^[12] that he suffered a version of Stockholm syndrome.^[13] According to The Guardian, Kennedy sued the police for ruining his life and failing to "protect" him from "falling in love" with one of the environmental activists whose movement he infiltrated.^[14]

In 2011, eight women who say they were deceived into having long-term intimate relationships by five officers, including Kennedy, who had infiltrated social and environmental justice campaigns, began legal action against the Metropolitan Police and the Association of Chief Police Officers (ACPO).^[15][16] A support group, Police Spies Out of Lives, has been set up not just to provide support for these women,^[17] but to also call for the Pitchford Undercover Policing Inquiry to investigate "all aspects of the complete disregard shown for human rights"^[18] and initiated a petition that it be "transparent, robust and comprehensive".^[19] Eventually, at least 12 women received compensation from the police in the High Court of Justice over similar issues, although the police avoided making internal documents about the relationships public.^[20]

Kennedy is one of several now-exposed undercover police officers profiled in the book Undercover: The True Story of Britain's Secret Police (2012).^[27] A planned television drama series is based on the story of the undercover officers.^[28]

The play Any Means Necessary is based on the infiltration of the Ratcliffe-on-Soar power station protest.^[29] It was the staged at Nottingham Playhouse in February 2016.^[30]

Andy Whittaker produced a series of podcasts for BBC Sounds about Kennedy. Whittaker looked at the effect the officer's actions had on the groups, friends and partners he became acquainted using his false identity. Called 'Undercover' it was released 23 January 2024.^[31]

• Covert policing in the United Kingdom
• Law enforcement in the United Kingdom
• Bob Lambert