Adric (Matthew Waterhouse)
The young Alzarian mathematician’s time with the Doctor came to an abrupt end when he died in an explosion while trying to regain control of a spaceship careering towards Earth. The end credits to part four of Earthshock roll in silence over a close-up of Adric’s shattered maths badge.
Donna Noble (Catherine Tate)
We may have glimpsed her second wedding day in The End of Time, but it’s Donna’s emotional departure as a travelling companion in Journey’s End that’s the true tearjerker. After assimilating the Doctor’s DNA, the Time Lord is forced to erase Donna’s memories in order to save her life.
Sarah Jane Smith (Elisabeth Sladen)
“Don’t forget me,” says Sarah Jane Smith at the end of The Hand of Fear. The Doctor has been summoned back to Gallifrey and realises he cannot take her with him. Of course, Sarah Jane would go on to have further encounters with the Doctor in his future incarnations, but here’s the moment that she first bid farewell back in 1976.
Astrid Peth (Kylie Minogue)
She may have only featured in one episode – 2007’s Voyage of the Damned – but to put things into context, this was Kylie Minogue being killed off on Christmas Day in front of 13 million viewers. Memorably, a teleport bracelet partially preserved her life force and the Doctor sent her out into space as a trail of stardust.
Rose Tyler (Billie Piper)
OK, so we know Rose returned to help the Doctor defeat the new Dalek empire, but this is Billie Piper’s exit as a series regular in Doomsday. Transported into a parallel universe after the Cybermen and Dalek armies are sucked into the Void, Rose cries a river over her separation from the Time Lord.