Happy Valley finale trailer hints at violent showdown between Catherine and Tommy

Watch: Happy Valley releases trailer for explosive last battle between Catherine and Tommy

Happy Valley has released an explosive trailer for Sunday's finale which hints at a dangerous showdown between Catherine Cawood and Tommy Lee Royce.

In one chilling scene, escaped convict Tommy (James Norton) appears to be hiding in the same house as police sergeant Catherine (Sarah Lancashire), who is on the hunt for her nemesis.

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Tommy has been clear about his intention to kill Catherine before continuing on the run to Malaga, but will he succeed?

Another scene shows Catherine panting and crying with blood on her face and looking devastated, apparently outside her own house.

Recent episodes showed murderer and rapist Tommy breaking out of court and going on the run with the help of drugs gang the Knezevics, but he has told would-be local politician and dangerous dealer Darius Knezevic that he intends to murder Catherine before taking her grandson Ryan (Rhys Connah) - his biological son - with him abroad.

Last week's episode left viewers wondering whether Ryan would turn against Tommy or Catherine as he struggled to fit in with his family and was contacted by his father via a games console.

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A scene from the trailer shows Ryan in a police interview room, being asked: "When was the last time you had any contact with Tommy Lee Royce?"

But viewers will have to wait for Sunday to find out whether he tells the truth.

Another scene shows Catherine's sister Clare (Siobhan Finneran) asking: "Have you caught him?"

Catherine warns ominously: "He's still out there. He's going to be angry, and he's going to be even more desperate and dangerous."

The finale on Sunday will conclude three seasons of the BBC One drama by Sally Wainwright, which had an eight-year hiatus before the current season to allow time for actor Connah to grow into a teen and his character to start to explore his own feelings about his father.

It returned at New Year to praise from fans, who have called for Lancashire to win awards for her performance.

Happy Valley concludes on Sunday at 9pm on BBC One.