Line Of Duty to return for a final 3 part series
 

According to the Sun, the show will return to put and tie up the storyline and reveal who H is and if what we know is a red herring.

Its expected to be back as early as next Xmas

As it should. I think everyone's in agreement that the ending was quite poor so it'll be nice for them to tie off some loose ends and go out with a bit more of a bang.