28/04/2017 11:23 BST | Updated 28/04/2017 12:34 BST

'Line Of Duty' Series 4 Final Episode 6 Sees Return Of Two Very Familiar Faces From Previous Series

Blasts from the past - why?

Viewers who’ve watched the preview for the final episode of this series of ‘Line of Duty’ will have noticed not one but two familiar faces appearing in some of the scenes. 

Their eyes are not deceiving them. The finale on Sunday evening sees the involvement of Murder Squad, drafted in because of everyone else’s compromised positions, which means the return to screen of both DS Sam Railston and Superintendent Lester Hargreaves. 

Sam (Aiysha Hart) is the former girlfriend of DS Steve Arnott, seen living with him in Series 3, when Steve came under suspicion by AC-12, because their own corrupt copper ‘The Caddy’ Dot Cottan managed to frame him. 

Sam Railston (Aiysha Hart) is back for the finale - what will Steve say?

Although she was seemingly troubled by the problems suffered by her boyfriend, it didn’t take long for Sam to join those doubting Steve, and finally did a bunk when he was briefly behind bars. How he’ll react to her return is just one of the fruity factors coming up in Sunday evening’s episode. 

Meanwhile, one of Hastings’ several Nemeses within the force Lester Hargreaves (Tony Pitts) is also back in town. Hargreaves, viewers will remember from Series 2, didn’t conform to quite the strict ‘Letter of the Law’ that Hastings reveres. And - guess what - his name, like that of Huntley, ACC Hilton and even Hastings himself, also happens to begin with an ‘H’. 

And Lester's back too...

Even without these returning characters, there’s a lot to play out in the finale, with actors Adrian Dunbar and Martin Compston both dropping hints in recent days as to the identity of Balaclava Man, and how he’s related to AC-12’s investigation into Roz Huntley’s deceptions.  

‘Line of Duty’ concludes on Sunday evening at 9pm on BBC One. 

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