Happy Valley creator and writer Sally Wainwright has revealed that a third run of the BBC's outstanding hit drama is on the way - but we won't see Sarah Lancashire back as Sergeant Catherine Cawood in the near future.

"It will happen, but it will be a little while," Wainwright said during a talk with former Doctor Who showrunner Russell T Davies at the Edinburgh International Television Festival. "I have got some good ideas," she added.

Happy Valley, starring Lancashire as the strong-willed Cawood and James Norton as her nemesis, Tommy Lee Royce, has been a huge success with critics and viewers alike since it debuted on the BBC in 2014.

The show has won a BAFTA for Best Drama, while Wainwright received the Best Writer: Drama prize at the BAFTA Television Craft Awards. Its second season was shown recently on RTÉ One.

The cast of Happy Valley also includes Rebellion's Charlie Murphy as police officer Ann Gallagher. The Love/Hate star recently reunited with Wainwright for an upcoming one-off drama about the Bronte sisters for BBC One, To Walk Invisible. Murphy plays the youngest sister, Anne, with the biopic telling the story of how Anne - author of the acclaimed novels Agnes Grey and The Tenant of Wildfell Hall - and sisters Emily and Charlotte came from obscurity to become literary icons. 

Charlie Murphy

In Edinburgh, Wainwright refused to give much away about other possible projects, but she teased that she's thinking of a musical for TV.

"It's on the way," she said. "It's an idea I have got for the screen that I am hoping to get away [made]."