HN8 is the cipher given to a former Special Demonstration Squad undercover officer who was deployed into one group in the 1980s/1990s. On 30 July 2018 John Mitting, Chair of the Undercover Policing Inquiry made a final ruling that real and cover name cannot be published by the Inquiry.
For the N cipher system see N officers page.
As an SDS undercover officer
HN8 was arrested in their cover name, though not charged. he reported this arrest to their manager. Others in their group were arrested the same day, with some being convicted of public order offices and fined. This arrest was for fly-poisting, and he was released without charge.
Was involved in the printing and circulation of the newspaper produced by the group they were targeting.States they did not use drugs or have sexual relationships while undercover
Joined Special Branch in the 1970s as 'always drive to understanding the most extreme forms of human functioning'. Joined SDS in late 1980s / early 1990s. 
HN8 has since left police and their new career involves activity which increases their public profile in their real name.
Says has maintained 'duty of confidentiality' regarding their career, even when asked publicly about it, and also stated:
- When I joined Special Branch I had an expectation that everything I did would be secret. In Special Branch confidentiality is all. The phrase was "need to know". I kept this promise rigidly and not just during my police career but subsequently to it as well. If I knew at the time that my real and or cover name was to be released I would never have undertaken the work.
HN8 concerned there is a risk to their safety and that of their children if cover name is released. The Risk Assessor for the Inquiry also found that if HN8's cover name was released, the risk of harm coming from some members of the target group was high, and potentially having serious impact, as some of HN8's former associates were 'known for violence'. The Risk Assessor also found that:
- If the dates of deployment, geographical area of operation and group infiltrated was confirmed, in the risk assessor's opinion, N8 would be remembered in N8's cover name, and would be exposed to the same risk...
In the Undercover Policing Inquiry
Currently in their 60s, the inquiry Chair, John Mitting has indicated he is minded to grant a restriction order preventing release of either cover or real name of the officers, stating in April 2018:
- The deployment was unremarkable. if the real or cover name of HN8 were to be published, there would be a real risk of interference in two aspects of the private life of HN8 - physical integrity and the ability to perform socially useful and remunerative work. The risk to physical integrity, which is real, if contingent, may arise from either members or associates of the group infiltrated. The risk to the ability to perform that work would arise from publicity in the traditional and non-traditional media. In neither case need the risk be run to permit the Inquiry to fulfil its terms of references. ... It would also not be in the public interest to run them.
- 3 July 2018: the Inquiry states Mitting remains minded to restrict both cover and real names, and issues open versions of the application documents:
- Open application for a restriction order (anonymity), Metropolitan Police Service, 23 March 2018.
- N8 - Risk Assessment (gisted), 8 May 2018, Adrian Baxter.
- Impact Statement of HN8, 5 April 2018.
- Inquiry's gist of additional information from HN8's closed risk assessment
- It was also directed that any objections to Mitting's intention to restrict the real name to be made by 20 July 2018.
- 30 July 2018: final ruling that real and cover name cannot be published.
- Sir John Mitting, In the matter of section 19(3) of the Inquiries Act 2005 Applications for restriction orders in respect of the real and cover names of officers of the Special Operations Squad and the Special Demonstrations Squad - 'Minded to' note 8, Undercover Policing Inquiry, 26 April 2018.
- Sir John Mitting, Applications for restriction orders in respect of the real and cover names of officers of the Special Operations Squad and the Special Demonstration Squad: Minded to note 12 and Ruling 10, Undercover Policing Inquiry, 30 July 2018.
- Inquiry's gist of additional information from HN8's closed risk assessment, Undercover Policing Inquiry, 2018.
- HN8, Impact Statement of HN8 (redacted), Metropolitan Police Service (Designated Lawyers Team), 5 April 2018.
- Adrian Baxter, N8 - Risk Assessment (gisted), Metropolitan Police Service, 8 May 2018 (accessed via ucpi.org.uk).
- Publication of documetns relating to anonymity applications: Special Demonstration Squad - November 2017, January 2018, March 2018 and April 2018 'Minded' to notes, Undercover Policing Inquiry, 3 July 2018.
- List of applications and evidence published on 03 July 2018, Undercover Policing Inquiry, 3 July 2018.
- Sir John Mitting, Restriction Order Applications by HN1, HN3, HN8, HN9, HN12, HN19, HN20, HN27, HN60. HN72, HN353 and HN355, Undercover Policing Inquiry, 3 July 2018.