VICKY McClure has become the queen of gritty dramas, such as This is England, Broadchurch and this acclaimed crime thriller.

However, the 30-year-old actress seems happy enough to be constantly surrounded by misery: “There are so many reasons why I came back to Line of Duty,” she says. “The scripts are really intelligent; when you first read them, you think they will need reading at least a few more times because you have to really think. I really enjoy TV that keeps you on your toes.”

This week, McClure’s character, Kate, remains undercover. She’s supposedly working on missing persons cases, but is really keeping an eye on DI Lindsay Denton in an attempt to find evidence that will prove she did have something to do with an ambush that left several of her colleagues dead.

Lindsay seems obsessed with the case of a 15-year-old girl, but as the investigation mounts, she becomes increasingly secretive and volatile.