Line Of Duty’s long-awaited sixth series has just got a thrilling new trailer, which hints DI Kate Fleming could suspected of corruption.

The minute-long clip gives fans of the hit BBC police drama their first full look at the upcoming episodes, which are set to debut later this month. 

In one ominous scene, we see the finger of suspicion pointed at Vicky McClure’s character, as DS Steve Arnott and AC-12 newcomer DC Chloe Bishop discuss who the fourth officer in league with organised crime could be. 

“Do you still believe there’s a fourth man out there?” Bishop asks. 

“Man? Or woman?” Arnott replies, before the camera cuts to shot of Fleming.

The end of series five revealed that the mysterious “H” figure was not actually a person, but a clue pointing at another high-profile police officer working with the organised crime group.  

Fans are also given the first look at the case serving at the backdrop to AC-12′s investigation into Detective Chief Inspector Joanne Davidson, who has previously been described as the “most enigmatic adversary” the team has faced so far. 

She is leading the investigation into the murder of journalist Gail Vella, with AC-12 tasked with establishing whether police corruption is the reason the case has gone unsolved. 

It is then revealed Gail has previously reported on the police corruption – could this be the reason for her murder?

There are also dramatic scenes including road accidents, police stand offs and shootings, as well as Superintendent Ted Hastings cracking under the pressure. 

A title card then menacingly warns: “Lies cost lives.”

The new series of Line Of Duty, which was delayed from last year due to the pandemic, sees Kelly Macdonald join the cast as DCI Davidson, along with Shalom Brune-Franklin as DC Bishop. 

Adrian Dunbar, who plays Hastings, previously revealed the first episode would be a “head wreck” for viewers as the action has moved on 18 months since the last series and many things have changed. 

“The landscape has completely changed,” Adrian told The Graham Norton Show. “We are starting from a place that the audience will probably find a bit shocking at first. 

“Things and people have been moved around so the first episode is going to be one of those ‘head-wrecks’ for the audience.”

Line Of Duty returns on Sunday 21 March at 9pm on BBC One, with the new season including an additional episode, with seven instalments instead of the usual six.