CHIS meaning: Line of Duty police acronym explained, what does it stand for – and why is it controversial?

‘CHIS’ is the latest piece of jargon befuddling Line of Duty fans on Twitter – here’s what it means, and a list of other policing terms found in the show

Last night (21 March) saw Line of Duty return with a bang, with the BBC’s blockbuster police corruption drama blasting back onto screens for its sixth series.

Known for its twists and turns, it can be hard to follow at the best of times, and a basic understanding of police force jargon is often required to make it through some of the more dialogue heavy scenes with your grasp on the plot intact.

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But things reached new levels in the opening episode of the show’s latest run, with the introduction of “CHIS”.

In the opening episode of Line of Duty's new series, the team were on the hunt for CHIS - but it's not as rude as it sounded (Photo: BBC)

The phrase caused so much confusion, the channel’s announcer was forced to issue an explanation as the instalment’s credits rolled, in response to a mass outpouring of confusion on social media.

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Add to the fact that many viewers mistook the acronym for a rude slang word for a particularly bodily fluid, and many fans were left scratching their head.

But what is a CHIS? Here is everything you need to know.

Priti Patel first introduced the Covert Human Intelligence Sources (Criminal Conduct) Act to Parliament in 2020 (Photo: Charlotte Graham - WPA Pool/Getty)

What is CHIS?

As the credits rolled at the end of the episode, the voice over said: "CHIS, if you're wondering, is a Covert Human Intelligence Source."

Always one for authenticity, Line of Duty proved itself to on the cutting edge of intelligence practises with the introduction of the term; the Covert Human Intelligence Sources (Criminal Conduct) Act 2021 only became law on 1 March 2021, three weeks before the new series’ debut.

The Act essentially allows Covert Human Intelligence Sources (undercover law enforcement agents and covert sources) working for bodies including police forces to “break the law in the interests of national security, the wellbeing of the UK's economy, or in order to detect or prevent crime and and the committing of crimes in the undertaking of their duty.”

Think James Bonds’ “license to kill” come real.

Who can issue CCAs?

The allowance of serious criminality through the issuing of a Criminal Conduct Authorisation or CCA can only be used “to prevent more serious crimes being committed and when there is no practicable legal path by which the same outcome could be achieved”.

Covert sources can even be aged under 18 or adults classed as ‘vulnerable’; in the cast of the former, Juvenile Criminal Conduct Authorisations (JCCAs) can be issued following risk assessments to determine that the covert source will not come to any harm.

CCAs can be issued by a number of government and regulatory bodies.

The list of powers that can use them include less surprising bodies like the police and the National Crime Agency, but the Environment Agency, Food Standards Agency and even the Gambling Commission can make use of the legislation should they need to.

The bodies capable of using undercover agents are:

Any police force
National Crime Agency
Serious Fraud Office
Any of the intelligence agencies
Department of Health and Social Care
Home Office
Ministry of Justice
Competition and Markets Authority
Environment Agency
Financial Conduct Authority
Food Standards Agency
Gambling Commission

Why was it controversial?

In December 2019, the Investigatory Powers Tribunal (IPT) held by a 3-2 majority that MI5 does have the power to authorise the commission of criminal offences by informants; a secret policy had been in place “since at least the 1990s” allowing MI5 to “authorise its agents to participate in serious crimes”.

In response, Home Secretary Priti Patel introduced the Covert Human Intelligence Sources (Criminal Conduct) Act to Parliament, but it faced widespread opposition – in February 2021, the Government saw off a bid by peers to explicitly ban the state from authorising undercover agents to kill, torture or rape.

Ministers had previously insisted there were already upper limits on what agents would be allowed to do under human rights legislation.

Speaking during consideration of Lords amendments to the Bill in the Commons, Solicitor General Michael Ellis said the Bill would resolve tensions over protection from prosecution.

“The Government introduced this Bill to provide a clear and consistent legal basis for the rare occasions where, in the course of their important work to keep us safe in that endeavour, it is necessary and proportionate for undercover agents to themselves participate in criminal conduct,” he said.

“This is a longstanding practice which has frankly proved critical in identifying and disrupting terrorist plots, drugs and firearms offences and child exploitation, sexual exploitation and abuse.”

The Bill was opposed by a number of political organisations and NGOs, including Labour and Liberal Democrat MPs, the Green Party, Scottish National Party, Sinn Féin, and Amnesty International, who described it as “hugely worrying” and “deeply dangerous”.

"MPs are signing off on a licence for government agencies to authorise torture and murder,” they said in a statement. “Giving such disturbing powers to bodies including MI5 and the police could have devastating impacts.”

What other acronyms do I need to know?

AC-12 – Anti-Corruption Unit 12
ACC – Assistant Chief Constable
AFO – Authorised Firearms Officer
ARU – Armed Response Unit
CC – Chief Constable
CPS – Crown Prosecution Service
CSE – Crime Scene Examiner
DC – Detective Constable
DCC – Detective Chief Constable
DCI – Detective Chief Inspector
DCS – Detective Chief Superintendent
DI – Detective Inspector
DIR – Digital Interview Recorder
DPS – Directorate of Professional Standards
DS – Detective Sergeant
Det Supt – Detective Superintendent
FI – Forensic Investigator
FLO – Family Liaison Officer
FME – Forensics Medical Examiner
IRV – incident response vehicle
MIT – Murder Investigation Team
MoPI – Management of Police Information
OCG – Organised Crime Group
PCSO – Police Community Support Officer
PNC – Police National Computer
PR – Police Regulations
RTC – Road Traffic Collision
RUC – Royal Ulster Constabulary
SCG – Serious Crime Group
SFC ­– Strategic Firearms Commander
SIO – Senior Investigating Officer
Sitrep – Situation Report
TA – Tactical Advisor
TFC – Tactical Firearms Commander
UCO – Undercover Officer