13/02/2014 04:23 GMT | Updated 13/02/2014 04:59 GMT

'Line Of Duty' Episode 1 Review - Back, Better Than Ever With Keeley Hawes In Fine, Enigmatic Form

Anyone worrying that 'Line of Duty' wouldn't be able to repeat the success of its debut series, would hopefully have found their fears assuaged after, oh, about five minutes.

Basically, as long as it took a witness protection exercise to go horribly wrong, cause the death of three police officers, and leave the witness fighting for his life in hospital, identity 'classified'.

Back in the line of fire...

And for its chief protagonist DI Lindsay Denton (Keeley Hawes) to emerge, unwillingly, into the spotlight. Head thrust down the toilet as she was shunned by fellow officers for leading colleagues to their deaths, and personal history thrust under the noses of the Internal Affairs team - dogged Martin Compston, enigmatic Vicky McClure and their boss, weary but gentle Adrian Dunbar.

One episode down, and this really could go any which way, with every character holding different secret cards, and you couldn't move for poker faces. When the Deputy Chief Constable visited the scene of the tragedy, was that a solemn countenance of mourning, or miscalculation? When DI Denton was repeatedly told she was being questioned as a witness, not a suspect, by our Internal Affairs bunch, why did she change her story about deciding the route of the ambush - just fear, or…. ?

Keeley Hawes as DI Denton - is she or isn't she?

This unforgiving scene, all close-ups and long silences, was an unblinking 10 minutes, and cut to the heart of what Internal Affairs have to do, in their unenviable task of policing the police. No wonder new recruit Georgia (Jessica Raine) took to drink. As for what happened to her, well… won't ruin it for iPlayer watchers, but bet NO ONE saw that coming.

MORE: 'I Felt Properly Sad Filming Line Of Duty,' Keeley Hawes Tells HuffPostUK

Writer Jed Mercurio has come up with a thrilling, multi-stranded sequel, easily as good, if not better, than Series 1. And Keeley Hawes is a revelation. As dowdy, down-at-heel, Denton, she could be either just a desperately unhappy woman, or something far more sinister, woefully unserved by her colleagues, or horribly unserving. I've watched this first episode twice now, and I have no idea.

'Line of Duty' is now on BBCiPlayer. Continues next week.