'Grantchester' stars Tom Brittney and Robson Green have hinted that the upcoming series will be the darkest yet.

Robson Green

Robson Green

Tom, who plays vicar and part-time detective Will Davenport in the detective drama, teased the upcoming episodes have "upped the murder count" and made for a much grittier show.

Tom told RadioTimes.com: "It's not Grantchester anymore, it's 'Dark-chester', it's 'Grit-chester'".

Robson, who plays Geordie Keating, a gruff detective who assists Tom in solving crime, suggested that this is the "best series yet" and deals with themes such as homophobia, racism and suicide, but insisted the "dark" material won't make it any less enjoyable for viewers.

He said: "We deal with very dark subjects that in no way deflects from its likability. It's how those themes affect those very, very likeable gallery of folk throughout the series is quite shocking."

The 55-year-old actor has seen "snippets" of the series and teased a plot twist where a seemingly-likeable 'Grantchester' character will reveal themselves to be "destructive".

Robson explained: "It's that whole notion - when you really thought you knew someone really well and then suddenly... you see it today, in the news, on social media, that this righteous person that's actually turned out to be a f**k-wit and an absolute f***ing nightmare of a person and a destructive individual.

"And with Grantchester you're taken along with these likeable character and then you just turn out to be destructive individuals, and you don't really see that scenario coming."

The 'Age Before Beauty' star also revealed that the series will include a "devastating" storyline between Geordie's wife (Kacey Ainsworth) and her mother, who Geordie invites to the family home to help out without informing his partner.

Robson said: "The secrets and lies about her life enter the environment and my (character's) wife never told me about it.

"It's things we harbour as individuals, they're very simple themes, but played beautifully within this scenario."

The fifth series of 'Grantchester' begins on ITV on January 10 2020.