Last night's Line of Duty episode has prompted a Home Office explanation of the work of undercover agents and the Covert Human Intelligence Source Act.
The BBC police drama began its sixth season last night and featured a 'Covert Human Intelligence Source' providing the name of a man who had admitted killing a journalist.
This morning on Twitter, the Home Office said: "For those who watched Line of Duty last night, CHIS stands for Covert Human Intelligence Source. The work of these undercover agents is vital in safeguarding victims from serious crimes including terrorism.
"In the last year, CHIS operations by the Met Police have led to 3,500 arrests, recovery of over 100 firearms and 400 other weapons, seizure of over 400kg of Class A drugs, and over £2.5m cash.
"Earlier this month, the CHIS Act was passed, ensuring our intelligence and law enforcement agencies continue to have the right tools to keep the UK safe, and to provide undercover agents with legal protection when carrying out their important work."
The Government's website says: "The Covert Human Intelligence Source (CHIS) provides a clear and consistent statutory basis so that our intelligence and enforcement agencies and public bodies have the right tools to keep us safe.
"This longstanding critical capability supports the work of undercover agents in preventing and safeguarding victims from serious crimes, including terrorism, by ensuring they can gain the trust of those under investigation.
"Robust independent oversight of the capability is provided by the Investigatory Powers Commissioner. All authorisations must be notified to his office within seven days of being granted, providing him with real-time oversight of all criminal conduct authorisations.
"He will also have oversight of the enhanced safeguards in place for juvenile and vulnerable adult CHIS."
