“Catherine Cawood works her final shift" - Final ever Happy Valley episode airs tonight

Millions are expected to tune into BBC One at 9pm to see the showdown of Catherine Cawood, played by Sarah Lancashire, and Tommy Lee Royce, played by James Norton.

A synopsis for the episode reads: “Catherine works her final shift, when scores are settled for good, while grandson Ryan faces a moral dilemma. The conclusion of Sally Wainwright's gripping drama about a Yorkshire police sergeant tormented by the ghosts of the past, starring Sarah Lancashire.”

The finale will be an extended episode to make sure to get as much of the drama in as possible.

Usually clocking in at around 58 minutes, the final episode of the popular BBC drama will run for one hour and eight minutes.

Writer Sally Wainwright has teased that there will be “big face-to-face showdown” this series, and with only one episode left it must be set to happen in the finale.

James Norton has spoken about how there are still some surprising things to come in the final episode.

Speaking to the Radio Time, he said: "The Sally signature is 'the rug pull' and there's a few of those still to come.

"Right until the end, it's surprising.

"Every time you get the scripts, you're like, 'She's done it again! She's not fallen short!' – not that she ever would. But there's always that thing of... is it going to be as good as the first two? And I think it's better!"

Happy Valley concludes on tonight (Sunday) at 9pm on BBC One