After a five-year hiatus, Wainwright has written six new episodes of the West Yorkshire set police drama, with Sarah Lancashire returning to her iconic role as Sergeant Catherine Cawood.

James Norton (McMafia) will reprise his role as Tommy Lee Royce, the murderer and sex-offender who assaulted Catherine’s daughter. Siobhan Finneran (Alma’s Not Normal) will also return as Catherine’s sister, the recovering addict Clare Cartwright.

The new series finds Catherine on the cusp of retirement, still battling with the seemingly unending problem of drugs and their suppliers in the valley. After the remains of a gangland murder victim are discovered in a drained reservoir, a chain of events is sparked leading Catherine straight back to her nemesis, Tommy Lee Royce. Her grandson Ryan has turned sixteen and is still living with her, but as he’s growing older, he’s beginning to have his own ideas about the kind of relationship he wants to have with the man who Catherine refuses to acknowledge is his father.

Happy Valley creator and writer Sally Wainwright said: “I'm delighted to find myself back in the world of Catherine Cawood and her family and colleagues for the final instalment of the Happy Valley trilogy. It’s been wonderful to see the lasting impact this series has had on audiences all over the world.

“I’m thrilled that Sarah, James and Siobhan are back on board for what I hope will be the best season yet and thrilled once again to be working with the wonderful team at Lookout Point, the BBC and our new colleagues at AMC.”

Sarah Lancashire added: “It’s time to let the dog see the rabbit.”

Filming will commence in and around West Yorkshire in 2022, with the new series premiering on BBC One and BBC iPlayer.