The episode Knock Knock has a pop at the current UK housing crisis.

Viewers will see The Doc’s companion and university canteen worker Bill Potts (Pearl Mackie) forced to move into a creepy old house with a bunch of students because they cannot afford anywhere decent.

When asked what other people do to avoid living in slums, Bill moans: “Other people have money.’’

Story writer Mike Bartlett tells Doctor Who Magazine: “Knock Knock is a little bit based on the housing crisis. More and more of us have to live with people we don’t know very well, in shared places.

“When you’re renting, you don’t always have a say over the conditions that you’re living in.”

The big “haunted’’ property in the episode might seem familiar too.

It is the same Grade II listed Victorian residence in Wales used in the 2007 story Blink featuring David Tennant as The Doc fighting off Weeping Angels.

Doctor Who continues tomorrow on BBC One at 7.20pm.