The Line Of Duty dictionary YOU need

If you found yourself baffled by the police jargon in last night’s episode of Line Of Duty then don’t fret, you are certainly not alone. 

Viewers took to Twitter to share their confusion as they struggled to keep up with a script peppered with dozens of acronym and abbreviations, some of which were integral to understanding what was going on. 

The acronym that garnered most attention was ‘CHIS’, or covert human intelligence source, which was repeated throughout the episode – and was misheard by some fans as a much cruder word. 

But there were plenty of others that had viewers flummoxed, including ‘AFO’, ‘DIR’ and ‘PNC’. 

Here, FEMAIL decodes some of the most important acronyms and abbreviations from last night’s episodes in a Line Of Duty dictionary…

Viewers took to Twitter to share their confusion as they struggled to keep up with a script peppered with dozens of acronym and abbreviations. Pictured, Ted Hastings (Adrian Dunbar) and Steve Arnott (Martin Compston) in last night’s series 6 premiere

AC-12: Anti-Corruption unit 12

The Anti-Corruption unit at the centre of the action in Line of Duty. Led by Ted Hastings, whose primary concern is ‘catching bent coppers’. 

DS Steve Arnott is one of his most trusted officers, although it looks like he might be ready to move on. DI Kate Fleming was a member of AC-12 until she left for the MIT (see below).

AFO: Authorised Firearms Officer 

An authorised firearms officer (AFO) is a police officer who has been selected, trained, accredited and authorised by their chief officer to carry a firearm operationally.

‘AFOs’ frequently appear in Line Of Duty and were deployed at the start of the episode in an operation to arrest the suspect in the murder of journalist Gail Vella.  

CHIS: Covert Human Intelligence Source   

Within the opening minutes of the episode, DCI Joanne Davidson (Kelly Macdonald) is discussing ‘intel’ (intelligence, see below), provided by a CHIS – but left viewers confused when no further explanation was given. 

CHIS stands for ‘Covert Human Intelligence Source’, or an individual who secretly provides the police with information that might help with ongoing cases. 

Police ranks you need to know 

In ascending order of seniority: 

DC: Detective Constable 

DS: Detective Sergeant

DI: Detective Inspector

DCI: Detective Chief Inspector 

Det Supt: Detective Superintendent 

DCS: Detective Chief Superintendent 

ACC: Assistant Chief Constable

DCC: Deputy Chief Constable

CC: Chief Constable

In the case of this episode, the CHIS was a ‘rent boy’ with information on journalist Gail Vella’s suspected killer who later died. 

DIR: Digital Interview Recording 

A recording made of a police interview. 

Occasionally interviewing officers will say phrases like: ‘For the DIR, the suspect is nodding their head’, in order to document a non-verbal response or event on the audio recording. 

Handler: Police force point of contact for informants 

A handler is a police officer involved in the day-to-day running of an informer or an undercover officer.

Last night’s episode saw DCI Davidson and DI Fleming quiz the ‘CHIS’ handler’, or the officer who liaised directly with an informant. 

Intel: Intelligence 

A simple abbreviation, ‘intel’ is used to mean ‘intelligence’ in police communications. 

MIT: Murder Investigation Team

In the first episode viewers learned DI Kate Fleming had left AC-12 following the scandal that engulfed DCS Ted Hastings at the end of series 5.  

She is now part of the MIT, or Murder Investigation Team, headed up by DCI Joanne Davidson. 

OCG : Organised Crime Group

Line Of Duty has thus far focused on a long-term investigation into the links between senior police officers and an ‘OCG’ or Organised Crime Group. 

How the current investigation ties into this overall story arch has yet to be revealed. 

Op: Operation 

Another abbreviation, ‘op’ is used to mean ‘operation’ in police communication. 

The ‘op’ at the centre of series six is Operation Lighthouse, which is investigating the murder of journalist Gail Vella.

PNC: Police National Computer 

The Police National Computer (PNC) is a system that stores and shares criminal records information across the UK.

Law enforcement agencies use it to access information that will support national, regional and local investigations.

DCI Davidson refers to the PNC in relation to trying to identify the suspect ‘Ross Turner’, revealing that the name who had brought up ‘no hits’, or there is no one with a criminal record with that name.  

SIO: Senior Investigating Officer 

In the police service a Senior Investigating Officer (SIO) is usually in command of a largely dedicated team of specialist trained and accredited officers, staff and experts from a Major/Serious Crime Unit/Division.  

DCI Davidson is the SIO in charge of Operation Lighthouse. DI Fleming is the Deputy SIO.   

UCO: Undercover Operative

Undercover Operatives are selected, vetted, trained and accredited to gather intelligence and evidence. 

UCOs are deployed in an authorised investigation or operation as a relevant source, which is defined as somebody who establishes and maintains a personal or other relationship with a person in order to obtain or provide access to information to another person, or to covertly disclose information obtained by the use of or as a consequence of the existence of such a relationship. 

DI Kate Fleming previously worked as a UCO.