The scenes saw Mitchell and Daisy embark on a killing frenzy on a train carriage full of people.

Answering questions on the show’s official blog, he commented: “Certainly storylining the Box Tunnel Massacre was a risk, because… it’s difficult to welcome someone back into our hearts after such a dark deed. But sometimes you have to obey the logic of a story regardless of what it does to our sympathy for the character.”

Whithouse continued: “With Mitchell it just felt inevitable that sooner or later he’d fall off the wagon. It also adds danger to the character and – I hope – a sense of exhilaration to the storytelling, because it means we’re off the map.”

He added: “If one of the main characters can do that, then absolutely anything can happen. But yeah, it was a huge decision because nothing could ever be the same again. It was a kind of Year Dot in character terms.”

The third series of Being Human continues with Episode 5 at 9pm on Sunday 20th February on BBC Three.

Watch a clip from Episode 5…