Not sure if anyone else here is watching this series but I'm finding it to be quite good. Not one of those special effects, lots of swearing etc type of police stories but is one with decent storylines. Maybe others will be able to pick holes in it but, for me, it's a series worth watching.
BUT. I will RECOMMEND that if you've never seen any of the previous four series, one being screened at the moment is series five, that you perhaps watch from series one which is available on Showmax. This will give you a better background to the different characters.
The fifth series of Line of Duty, consisting of six episodes, began broadcasting on 31 March 2019 on BBC One. The series follows the actions of Superintendent Ted Hastings (Adrian Dunbar), D.I. Kate Fleming (Vicky McClure) and D.S. Steve Arnott (Martin Compston) as they investigate an Organised Crime Group with links to missing undercover officer D.S. John Corbett (Stephen Graham). Anna Maxwell Martin stars in episodes five and six as D.C.S. Patricia Carmichael. Supporting characters include underboss Lisa McQueen (Rochenda Sandall) and the special counsel to the police and crime commissioner Gill Biggeloe (Polly Walker).