Unusually for a crime drama, there are no car chases, shoot-outs, explosions, kidnappings or violent attacks in Netflix's Criminal. Well, not on screen anyway.

The series is set almost entirely in a police interview room, where suspects (played by a guest cast including David Tennant and Hayley Atwell) are interrogated as detectives try to ascertain their guilt or innocence.

Without being shown the crimes in question, our opinions as viewers are formed purely on the basis of what the suspects say and how they behave in their interviews.

The only other two places seen in Criminal are the adjoining observation room, where police can watch what's going on from the other side of a two-way mirror, and an area outside where detectives can get a coffee on their breaks.

"We were really excited by that constraint," says George Kay, showrunner and writer on Criminal. "Because I think, without being too grand, you don't need any more than three rooms in any kind of drama.

"You've got the action, the observation room next door, and a third space, which we always had as an unofficial rule where people would tell the truth or take a breather, the kind of downtime space.

"I always had the feeling that I never needed to find another space - there is always a solution to be found in the next room along. And so we're just rotating these, the characters and their situation and complicating it."

Often, TV series use a changing backdrop as a way to keep viewers engaged.

Political drama The West Wing, which was set in the fairly dark and drab halls of The White House, became famous for its so-called "walk and talk" scenes, where key conversations between characters would take place on walks through the halls between meetings.

The busy, bustling backgrounds helped keep viewers engaged during scenes where the characters were sometimes discussing the more mundane elements of government legislation.

But when you're confining your storyline to a single location, there are limited tactics a writer and director can employ.