The Metropolitan Police Service (MPS) has formally apologised to Hampshire Constabulary for an incident regarding the actions of the former undercover unit - the Special Demonstration Squad (SDS).
During the investigation into the SDS carried out by Operation Herne the MPS found information about the deployment of an undercover officer known as 'Christine Green'. Christine Green infiltrated the Animal Liberation Front (ALF) and London Animal Action between 1994 and 1999.
It appears from the available evidence that Christine Green was authorised by her then line management, potentially up to the rank of Detective Chief Superintendent, to participate in a criminal act that took place on the night of 8 August 1998. This was when ALF activists released a large number of mink from a fur farm - Crow Hill Farm - in Ringwood, Hampshire.
A decision was made by the SDS not to share Christine Green's involvement or the knowledge the MPS had about the role of the ALF with Hampshire Constabulary, who carried out a criminal investigation at the time. In 2014, the MPS disclosed the former officer's role to Hampshire Constabulary. Neither the MPS nor Hampshire Constabulary could share this more widely at that time in view of the risk of identification of the former officer.
At this stage there is no evidence that the officer was involved in the second release of mink two weeks later. She resigned from the MPS in August 2000.
The MPS has informed the Public Inquiry into Undercover Policing of this matter. Following the Chairman Sir John Mitting's ruling regarding the release of the former officer's cover name, the MPS agreed that it was in the public interest that the role of the MPS in this incident be made public.
Assistant Commissioner Helen Ball, in charge of Professionalism in the MPS, said: "The MPS has apologised to Hampshire Constabulary for the impact these decisions had on their ability to bring those responsible to justice.
"The precise circumstances of the decision to authorise an undercover officer to participate in this criminal act will be fully explored as part of the Public Inquiry process. I would like to be clear that the decision making surrounding this incident would simply not happen in today's Metropolitan Police Service.
"It appears that the SDS allowed this incident to go ahead, as they saw it, in the interests of preventing more serious crime in the longer term. The scale of the release was unforeseen by the SDS at the time, but once the impact became clear they still did not inform Hampshire Constabulary of the officer's involvement.
"It is not possible to say what direct impact the role of Christine Green's involvement had or if different policing decisions could have averted the damage.
"I do understand that this decision making from 20 years ago will cause significant concern to the public, especially those people directly affected by the events in 1998. The MPS will be honest about our past and accept criticism where it is due.
"Today, undercover policing is extensively supervised, including by the Investigatory Powers Commissioner and Her Majesty's Inspectorate of Constabulary and Fire and Rescue Services. We work within this framework to use undercover policing tactics appropriately for the benefit of the public. We have a continuing responsibility to reassure the public about the ethics and integrity of modern policing."
A referral was made to the then Independent Police Complaints Commission in April 2014 with regards to the role and conduct of Christine Green. The IPCC decided a local investigation should be carried out - this was conducted by Operation Herne under the supervision of then Derbyshire Chief Constable Mick Creedon. An investigation was carried out within the frameworks available at that time and a file was submitted to the CPS in December 2015. In February 2016 the CPS advised there was insufficient evidence to provide a realistic prospect of conviction.
The work of Operation Herne remains ongoing.
The Public Inquiry published the former officer's cover name on Tuesday, 20 February. A restriction order has been granted over her real name.