10 Even MORE Doctor Who Episodes You Didn't Know Were Connected

The Peter Cushing Dalek movies take place in an alternate reality to the prime Doctor Who universe. However, they've had a big influence on the modern era of the show, particularly in the design of the Daleks.

Since 2005, Daleks have had the larger dome lights of the Cushing movie versions, and the short-lived colourful Daleks from 2010 owe a major design debt to their chunkier technicolour ancestors.

The biggest influence though was a bit of Dalek lore that had first been mentioned onscreen in 1966's Daleks' Invasion Earth 2150 AD.

This second Peter Cushing movie established that Daleks measure time in rels. The word "rel" had been introduced by Dalek creator Terry Nation in his 1960s tie-in books, but Daleks' Invasion Earth 2150 AD was the only onscreen source to use it... until 2006.

40 years after Daleks' Invasion Earth 2150 AD hit cinemas, Russell T Davies canonised the use of rels in the prime Doctor Who universe, in the episode Doomsday. When the Cult of Skaro is looking at some footage and notices the Tenth Doctor in the background, it is instructed that this footage be rewound by nine rels.

From that moment on, the new series Daleks have measured time in rels, even though nobody is entirely sure how long a rel is. Though based on the rel counter pictured in Daleks' Invasion Earth 2150 AD, it appears that 50 rels is equivalent to 60 seconds.