Line Of Duty’s explosive third series concluded on Thursday with fictional anti-corruption police unit AC-12 putting away bent officers, past and present.

And it’s now been revealed that series four of writer Jed Mercurio’s hit drama will begin filming in August. It is likely to air in 2017.

This run has been a phenomenal success for BBC Two. The gritty cop drama, which stars Martin Compston, Vicky McClure and Adrian Dunbar as Detective Sergeant Steve Arnott, Detective Constable Kate Fleming and Superintendent Ted Hastings respectively, drew a whopping overnight average of 4.1 million viewers for its feature-length finale.

Daniel Mays in BBC Two's Line Of Duty
Daniel Mays in BBC Two’s Line Of Duty (Steffan Hill/BBC/World Productions)

Featuring Daniel Mays as Sergeant Danny Waldron and Keeley Hawes as Detective Inspector Lindsay Denton, the BBC drama made by World Productions has frequently averaged more than three million viewers in the overnight ratings.

Last week’s penultimate instalment concluded with the shocking death of DI Denton, a magnificent portrayal by The Durrells’ Keeley, and drew 3.4 million.

Consolidated figures, which include viewing on the night of transmission and people who recorded the show and watched it in the subsequent seven days, have so far seen the BBC Two series well over the five million mark.

Martin Compston and Adrian Dunbar in Line Of Duty
Martin Compston and Adrian Dunbar in Line Of Duty (Mark Bourdillon/World Productions/BBC)

Kudos to writer Jed for crafting a drama which continues to be so much more than just a story of corrupt or amoral cops. From a seemingly simple premise, we’ve watched over two nail-biting series as those who are sworn to uphold the law invariably break it and lose their moral centre.

Keeley Hawes in Line of Duty (World Productions/BBC)
Keeley Hawes in Line Of Duty (World Productions/BBC)

Each series has upped the stakes involved and built the tension to an unbearable level, wrong-footing fans and critics alike with more twists than Spaghetti Junction.

Social media was awash with tweets from viewers praising the series for its writing and direction.