This episode goes behind the scenes of The Stolen Earth

With The Doctor's oldest adversaries back and badder than ever, a look inside the dark and deadly world of the Daleks. From their creation 45 years ago to their latest incarnation, the lid is lifted on TV's most popular aliens.

Learn what first inspired the iconic Dalek design, see how they are brought so terrifyingly to life, and discover just what Daleks get up to between takes when they're not conquering the universe.

With exclusive interviews from David Tennant, Russell T Davies, director Graeme Harper, art director Ed Thomas and original Dalek designer Ray Cusick, Confidential gets the inside story on the grand designs that make this show look so good.

Plus, as all the different Doctor Who worlds collide, the biggest ever collection of companions are quizzed on what it's been like teaming up to take on the evil exterminators.