4Z. The Invasion Of Time
The Doctor starts to behave out of character after a mysterious meeting in space with a group of aliens. On returning to Gallifrey the Doctor speaks with Borusa and claims his right to the Presidency.
The Vardans, a telepathic race, have managed to gain access to the Matrix. As President the Doctor has access to the Coronet of Rassilon which links him with the Matrix. Fearing that the Vardans may read Leela's mind, which could jeopardise his plan, he pulls rank and banishes her to the wastelands of Gallifrey.
The Doctor links K-9 into the Matrix to find the Vardans' point of origin without rousing their suspicions in order to be able to place a time loop round their planet. When the Doctor finally springs his trap and banishes the Vardans Gallifrey is invaded by the Sontarans.
The Sontarans had been using the Vardans to help them in the invasion of Gallifrey. Using knowledge from the Matrix the Doctor manages to construct the forbidden de-mat gun, controlled by the Great Key of Rassilon. He uses the device to destroy the Sontarans, although his memory of the events is erased. Leela announces that she wishes to stay behind with Commander Andred, and so too does K-9.
- Leela: Louise Jameson
- Voice of K-9: John Leeson
- Castellan Kelner: Milton Johns
- Commander Andred: Christopher Tranchell
- Chancellor Borusa: John Arnatt (1-3,5-6)
- Vardans: tan McGowan (1-4), Tom Kelly (1,2,4)
- Lord Gomer: Denis Edwards (1-3)
- Gold Usher: Charles Morgan (1-3)
- Lord Savar: Reginald Jessup (1)
- Rodan: Hilary Ryan (2-6)
- Guard: Christopher Christou (2)
- Nesbin: Max Faulkner (3-6)
- Presta: Gai Smith (3-6)
- Ablif: Ray Callaghan (3-5)
- Jasko: Michael Mundell (3-5)
- Bodyguard: Michael Harley (3)
- Commander Stor: Derek Deadman (4-6)
- Castellan Guard: Eric Danot (4)
- Sontaran: Stuart Fell (4-6 - uncredited for 4)
- Guards: Michael Harley (1-3), Eric Danot (1-3)
- Outsiders: Alan Forbes, Bobby James, David Melbourne, Mike Mungarvan
- Extras: Laurie Goode (3), Martin Grant (1-4), Mark Holmes (4), Julian Hudson (4), Derek Hunt (4), Mort Jackson (1,2,4), Giles Melville (1-4), James O'Neill (2), Buddy Prince (1-4), Martin Richards (5-6), Norman Rochester (5-6), Peter Roy, Tony Snell (1-4), Michael Sliwoski (1-2), Robert Smythe (1-2), Robert Tucker (2)
|BBC 1||474. Part One||Saturday, February 4, 1978 6:25 PM - 6:50 PM||11.2M||56%|
|BBC 1||475. Part Two||Saturday, February 11, 1978 6:25 PM - 6:50 PM||11.4M|
|BBC 1||476. Part Three||Saturday, February 18, 1978 6:25 PM - 6:50 PM||9.5M|
|BBC 1||477. Part Four||Saturday, February 25, 1978 6:25 PM - 6:50 PM||10.9M|
|BBC 1||478. Part Five||Saturday, March 4, 1978 6:25 PM - 6:50 PM||10.3M|
|BBC 1||479. Part Six||Saturday, March 11, 1978 6:25 PM - 6:50 PM||9.8M|
- Television Centre Studio 8
- Hammersmith, London
- Laporte Industries Sandpit, Redhill, Surrey
- St. Anne's Hospital, Redhill, Surrey
John Leeson's K-9 voice is not heard in Part Five
Louise Jameson leaves at the end of the story.