Line of Duty season 6 final episode trailer hints at H reveal and explosive action

Line of Duty has dropped an explosive trailer for its much-anticipated season six finale – and it looks like we might finally get an answer to the question, 'Who is H'?

The action-packed teaser promises that "Every investigation has led to this" before cutting to an ominous shot of AC-12's investigation board – with a spot yet to be filled by 'H', a.k.a. the Fourth Man.

We also get brief glimpses of some of the police officers suspected to be the figurehead of institutionalised corruption – Patricia Carmichael (Anna Maxwell-Martin), Chief Constable Philip Osborne (Owen Teale) and the apparently deceased Marcus Thurwell (James Nesbitt).

Another hint comes with a shot of a police document featuring a misspelling of the word "definite" – similar to how 'H' previously misspelt "definately" in communications with his cronies.

The possible unmasking of 'H' isn't all we've got to look forward to either, as we also get a glimpse of an armed police operation, with Steve Arnott (Martin Compston), Kate Fleming (Vicky McClure) and Chloe Bishop (Shalom Brune-Franklin) all in the fray.

Jo Davidson (Kelly Macdonald) – who was arrested in the most recent episode – is also seen being taken away by police transport. Something's bound to go wrong there, right? Just ask Jimmy Lakewell...

For more Line of Duty coverage, read our Line of Duty episode 6 recap, our ode to Carmichael and our explainer on Jo Davidson's 'father'.

Line of Duty season six concludes this Sunday at 9pm on BBC One – take a look at the rest of our Drama coverage, or check out our TV Guide to see what’s on this week.