The sixth series of Line of Duty started filming this week and show creator Jed Mercurio has taken to Twitter to share an alarming 'publicity shot'.

The snap shows stars Martin Compston and Vicky McClure, in character as Steve Arnott and Kate Fleming, pointing their guns towards each other while Ted Hastings (Adrian Dunbar) lies apparently slain, marked with a large 'H' sign – a reference to the code name given to the corrupt copper at the heart of the force.

The photo is clearly a joke, however, and not a real still from the upcoming series, so fans would be wise not to look too deeply into it.

Mercurio included a caption with his tweet, which read: "A great first week of filming #LineofDuty Series 6 ⁦@BBCOne @worldprods with @martin_compston @Vicky_McClure Adrian Dunbar. Here’s a publicity shot that’s been approved 100% spoiler free by ⁦@bbcpress.

The sixth series of the police corruption thriller will be set a year and a half on from the events of series five, and will feature a brand new case for AC-12, focused on an enigmatic Detective Chief Inspector.

It's not yet clear exactly when it will air, but we do know that Kelly Macdonald (Trainspotting, Giri/Haji) is joining the cast as this year's guest lead.

She will play DCI Joanne Davidson, “the senior investigating officer of an unsolved murder, whose unconventional conduct raises suspicions at AC-12," with other new cast members including Shalom Brune-Franklin (Our Girl), Andi Osho (Kiri) and Prasanna Puwanarajah (Doctor Foster).

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All previous series are available to watch on BBC iPlayer.