The show from genius Jed Mercurio, starring Adrian Dunbar, Vicky McClure and Martin Compston began in 2012 and has treated us to six series (so far…?). Season six ended in May 2021, and, even though it was pitched as the final season, there are rumours of a shorter season seven to tie up any loose threads – or lost leads. Reports suggested that Line of Duty would air new "special episodes" with a potential three-parter being planned. Apparently, someone with a close knowledge of the show said that "there's a strong feeling that there was unfinished business". Yeah, that's probably an understatement. World Production // BBC But while we wait, let's have at the show so far and how each series ranks. And let's be clear from the off – there are no bad series of Line of Duty. But we like some more than others. Watch out, fellas – spoilers follow. 6th. Series Four (2017) BBC Related: Line of Duty series 6 release date, episodes, cast, plot and all you ne...