If UK police drama Line of Duty has shown us anything over the years, besides the fact that Adrian Dunbar’s glare could wither an oak tree, it’s that entertainment can be educational too.
Amid the high-octane scenes of crime and corruption, the BBC One series has never shied away from subjecting its viewers to a whole host of police acronyms and abbreviations.
Whether this be the name of Ted Hastings’ fictional anti-corruption unit AC-12, or its frequent references to OCGs and AFOs (if you haven’t picked these up by now, we can’t help you), the series is packed to the brim with immersive – albeit sometimes mildly confusing – details such as these.
And it appears that the show’s writer Jed Mercurio sees no reason to alter course with season six, which debuted on Sunday at 9pm.
The new season came equipped with yet another acronym for you to learn.

Those tuning in on Sunday soon found themselves having to get their head around the acronym, “CHIS”, as detectives delved into another murder mystery.
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The real-life acronym stands for “covert human intelligence source” – or, in layman’s terms, an informant.
The BBC voiceover even clarified what the term meant as the show ended. But, without any explanation given by the characters, viewers flocked to Twitter to ask what it meant.
Be honest... who has googled ‘CHIS’? ✋🏻✋🏻✋🏻 Covert Human Intelligence Source. #LineOfDuty— Dan Walker (@Dan Walker) 1616362670
Line of Duty S6E1 recap #NoSpoilers #LineOfDuty https://t.co/AqtYt4IQm2— TwistedDoodles (@TwistedDoodles) 1616364597
Me missing half the story because I'm googling CHIS #LineOfDuty https://t.co/XqQMdVcaXd— Michelle (@Michelle) 1616364573
everyone hearing “chis” and just having to go along with it #LineofDuty https://t.co/FMDesK1eFL— 🤍 (@🤍) 1616364558
me trying to figure out what CHIS was #LineofDuty https://t.co/rN1fXK0Pcn— naomi (@naomi) 1616364492
Mother of god SO.MANY.ACRONYMS!!!! CHIS, JIZZ, UCO, DIR, MIT, ARU, ARV, B&E. anyone in need of a jargon buster to u… https://t.co/U7cS8mogoF— Katy Dixon (@Katy Dixon) 1616363463
2020 gave us the word furlough. 2021 has given us the word chis. #LineofDuty— Helen Scott (@Helen Scott) 1616363875
Presenter Richard Osman wondered if it was a clue to the identity of H - the apparently one remaining corrupt police officer that Ted and co are trying to track down.
So they're telling us CHIS stands for 'Covert Human Intelligence Source'. But what if CHIS really stands for 'Clear… https://t.co/rfRqGEJd70— Richard Osman (@Richard Osman) 1616364687
Others viewers misheard the acronym and the term, errr, “jizz” started trending on Twitter.
Google searches for #chis went through the roof in the last hour... once everyone had got over the initial #jizz co… https://t.co/1w5tJ4Kc4p— Alex James Duckett (@Alex James Duckett) 1616364567
Dear #LineOfDuty please stop saying Jizz Handler as we are not mature enough to deal with it.— Kate (@Kate) 1616362541
Some helpful fans just took it as an opportunity to explain all the other terms that have become part of any LOD aficionados’ lingo and might well come in handy over the next five weeks.
Save this..... you’ll need it for next 6 weeks....#lineofduty https://t.co/KtAirD9S1y— Tracey Cawthra (@Tracey Cawthra) 1616365793
And others didn’t really understand what any of it meant, but had a jolly good time watching it anyway.
Haven’t got a clue who’s been murdered Not a scooby who the suspects are Not the foggiest who Kate’s working for… https://t.co/XIvXo2Tp5O— David Nash (@David Nash) 1616364333
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