"HMIC's review rightly recognises the critical role undercover officers play in gathering evidence and intelligence to protect communities from harm. We should not underestimate the considerable risk that officers within this arena put themselves at in order to protect our communities.

"It is hugely important that the public has confidence that police use of these vital tactics is lawful, ethical, necessary and proportionate. HMIC's review finds that significant work has been done to improve the way police deal with undercover operations. The scrutiny and supervision of these types of operation are now far more intrusive than they have ever been. However, there is more to do to ensure that undercover policing is effectively utilised and regulated and ACPO will continue to work with the government, College of Policing, the Office of the Surveillance Commissioners and HMIC to achieve this."