PP. The Enemy Of The World
The TARDIS materialises on a beach in Australia in the near future. The Doctor, Jamie and Victoria are attacked by a hovercraft, and are rescued by a helicopter pilot named Astrid.
Astrid's boss, Giles Kent, explains that the Doctor is an exact double of the Salamander, a scientist and politician who has found a way of ending starvation in a world ravaged by natural disasters. Salamander is hailed as hero, although some people see him establishing a dictatorship.
Jamie and Victoria find that the Salamander is responsible for the natural disasters. The Doctor, taking on the identity of the Salamander, manages to get inside the research station and gain access to the Salamander's files.
Kent is exposed as a traitor, and blows up the research station. The Salamander tries to take on the identity of the Doctor and steal the TARDIS. He forgets to close the doors on dematerialisation and is sucked out into the vortex.
- Jamie McCrimmon: Frazer Hines
- Victoria Waterfield: Deborah Watling
- Giles Kent: Bill Kerr
- Donald Bruce: Colin Douglas
- Astrid Ferrier: Mary Peach
- Anton: Henry Stamper (1)
- Rod: Rys McConnochie (1)
- Curly: Simon Cain (1)
- Salamander: Patrick Troughton (2-6)
- Benik: Milton Jones (2-6)
- Fariah Neguib: Carmen Munroa (2-4)
- Alexander Denib: George Pravda (2-3)
- Fedorin: David Nettheim (2-3)
- Guard Captains: Gordon Faith (2), Elliot Cairnes (4-6)
- Griffin: Reg Lye (3)
- Guard on Denes: Bill Lyons (3)
- Guard in Corridor: William McGuirk (4-6)
- Swann: Christopher Burgess (4-6)
- Colin Redmayne: Adam Verney (4-6)
- Mary Smith: Margaret Hicket (4-6)
- Sergeant to Benik: Andrew Staines (4)
- Fighting Guard: Bob Anderson (4)
- Guard in Caravan: Dibbs Mather (4)
- Guards: Denis Balcombe, Peter Bennett, Eric Bird, Paul Blomley, Drew Borland, Gary Dean, Tony Franks, Ken Frazer, Richard Knight, Charles Mylne, Jay Neill, Tony Norman, Blair Stewart, David Troughton
- Central European Guards: Andrew Andreas, Harry Fielder, Ian Hines
- Extras: Peter Diamond, Pat Gorman, Richard Halifax, Arthur Maguire, KR Morgan, Vic Taylor
- Shelterers: Francis Batsoni, John Clevedon, Ruth Harrison, Pearl Hawkes, Bill Howes, Sarah Lisemore, Deborah Miller, Geoffrey Obert, Rosina Stewart, Valerie Taylor, John Timberlake, Freddie Whiles
|BBC 1||186. Episode 1||Saturday, December 23, 1967 5:25 PM - 5:50 PM||6.8M||50%|
|BBC 1||187. Episode 2||Saturday, December 30, 1967 5:25 PM - 5:50 PM||7.6M||49%|
|BBC 1||188. Episode 3||Saturday, January 6, 1968 5:25 PM - 5:50 PM||7.1M||48%|
|BBC 1||189. Episode 4||Saturday, January 13, 1968 5:25 PM - 5:50 PM||7.8M||49%|
|BBC 1||190. Episode 5||Saturday, January 20, 1968 5:25 PM - 5:50 PM||6.9M||49%|
|BBC 1||191. Episode 6||Saturday, January 27, 1968 5:25 PM - 5:50 PM||8.3M||52%|
- Ealing Television Film Studios
- Lime Grove Studio D
- Littlehampton, West Sussex
- Villiers House, Redhill, Surrey
Frazer Hines and Deborah Watling are not in part four.
David Troughton, son of Patrick, who is set to later appear in The War Games and The Curse of Peladon, appears uncredited as a guard in this story.