It's been an agonising wait for Happy Valley fans — but series two begins on BBC One next week.

The gritty drama, filmed around Sowerby Bridge, Halifax and Huddersfield, returns on Tuesday at 9pm.

Sarah Lancashire, who plays Sgt Catherine Cawood, has revealed what's in store for her character in series two — from finding a body in the first episode, to clashing with new characters.

Happy Valley
Happy Valley

Sarah Lancashire on Happy Valley series two:

Did you expect the first series to be such a success?

You know when a script is good, but you don’t have any knowledge how visually it is going to look. When this came out and I saw the first episode and thought it was terrific.

Why do you think it struck such a chord with people?

I would like to think that the piece as a whole, the characters, the story, were all so engaging and really captured people’s imaginations. I also think that the production value is very high on this.

Where do we find Catherine when the series begins?

It is 18 months later, so Tommy has been in prison for a year and a half. He was charged with three murders so he is not coming out. Catherine finds a body in episode one and the rest of the series unfolds from there.

Do Catherine and Tommy have two separate stories in this series?

Yes, as Tommy is in prison. We don’t strictly encounter each other in this series. We do meet but our stories are kept quite isolated.

Happy Valley: Sgt Catherine Cawood , played by Sarah Lancashire
Happy Valley: Sgt Catherine Cawood , played by Sarah Lancashire

There has been a lot said about the violence towards women in particular. What do you think about the violence?

Catherine is a police officer and the violence she was subjected to in series one is what female police officers can be subjected to every day of the week. I would never condone anything which I thought was salacious, titillating, or gratuitous. If you replayed the violence from series one, what you think you saw you probably only heard because it was shot beautifully. It was an absolutely honest portrayal of what a female police officer can be subjected to.

How does Catherine Cawood get on with other new members of the team, eg John Wadsworth (Kevin Doyle) and Jodie Shackleton (Katherine Kelly)?

It is very interesting because they are CID. They have been brought into the building to investigate what appears to be a serial killer. She loathes Jodie Shackleton simply because she used to be CID and she knows how CID works.

What sort of reaction have you had from female police officers?

The feedback we had was that they had never seen a police officer portrayed accurately and that Catherine Cawood is a great portrayal of police officer. This is down to Lisa Farrand who was our police advisor. She is retired from the force now but she was a sergeant and whenever we do any sort of procedural stuff Lisa is with me. She takes no nonsense and gets on with the job.

Does the series still maintain its characteristic humour despite the difficult storylines?

Yes, Catherine’s dark humour is present all the way through. Remember how Steve Pemberton’s character got deeper and deeper until he got too deep? It’s the same with Catherine.