Line of Duty teaser hints at "tragic events" in episode 5

BBC One's episode description for Sunday's episode hints that we'll see Superintendent Ted Hastings' authority undermined, which then "leaves his team in a potentially dangerous situation".

While we don't know what that situation could be, the description for the following instalment, episode six, teases: "As AC-12 struggle to deal with the repercussions of tragic events, Hastings makes one final bid to uncover institutionalised corruption before his time runs out."

With it being Line of Duty, we know that none of the characters are safe – a fact confirmed by Jed Mercurio last August when he revealed that "there's a sword hanging over every single one of" the main AC-12 trio – Arnott, Fleming and Hastings.

We don't yet know exactly what the "tragic events" of episode five will be, but judging by the first-look pictures for this Sunday's instalment, it looks as though Steve Arnott (Martin Compston) will be rushing into a potentially risky environment.

In a teaser shot released by the BBC ahead of episode five, we see Steve reaching for his gun whilst on the move in a bulletproof vest while, in another picture, we see him working alongside a shocked-looking Jo Davidson, still wearing the same clothes.

First-look images for Sunday's episode released earlier this week also revealed the return of Detective Chief Superintendent Patricia Carmichael, played by Anna Maxwell Martin, who was introduced last series when she grilled Ted Hastings about his suspicious behaviour.

Line of Duty continues on Sundays on BBC One. Check out the rest of our Drama coverage, or take a look at what else is on this week with our TV Guide.