5A. The Ribos Operation

Season Sixteen - 1978/1979 (The Key To Time)

Script Editor: Anthony Read
Writer: Robert Holmes
Produced by: Graham Williams
Director: George Spenton-Foster
Designer: Ken Ledsham
Incidental Music: Dudley Simpson


The Doctor is chosen for a very special mission - to retrieve and assemble the Key to Time - by none other than the White Guardian. The Doctor is also provided with a new companion, the Time Lady Romana, and warned that there is also a Black Guardian who will do all in his power to obtain the Key to Time.

The Doctor is also provided with a Tracer which will locate each of the segments, and it leads the TARDIS to the planet of Ribos, where two con-men are attempting to sell the planet to the Graff Vynda-K. To make the planet look more valuable the leader, Garron, plants a lump of Jethryk as bait, whilst Unstoffe pretends to be a local talking of a Jethryk mine.

The Graff Vynda-K discovers that Garron and Unstoffe are con-men, and pursue them into the catacombs, where the natives fear to tread. Several fights break out, and the Graff Vynda-K's men are all destroyed. The Doctor disguises himself as one, and the Vynda-K tries to use him to deliver a bomb, but the Doctor switches it back, and the Vynda-K is destroyed.

Romana uses the tracer and the Jethryk transforms into the first segment of the Key to Time.

Regular Cast

  • Voice of K-9: John Leeson
  • Romana: Mary Tamm

Guest Cast

  • Garron: Iain Cuthbertson
  • Unstoffe: Nigel Plaskitt
  • Graff Vynda-K: Paul Seed
  • Sholakh: Robert Keegan
  • Captain: Prentis Hancock
  • Shrieves: Oliver Maguire, John Hamill (1-2)
  • The White Guardian: Cyril Luckham (1)
  • Binro the Heretic: Timothy Bateson (3-4)
  • The Seeker: Ann Tirard (3-4)
  • Walk-On Shrieves: Roy Brent, Yuri Gridneff, Barry Summerford, David Young
  • Shrivenzale: Stuart Fell (1-2), Nick Wilkinson (1-2)
  • Krole: Pat Gorman
  • Leviathans: ony Bell, Derek Chafer, Harry Fielder, Steven Ismay

Original broadcast on the BBC

Channel Title Date Viewers Rating
BBC 1 480. Part One Saturday, September 2, 1978 5:45 PM - 6:10 PM 8.3M 59%
BBC 1 481. Part Two Saturday, September 9, 1978 6:20 PM - 6:45 PM 8.1M
BBC 1 482. Part Three Saturday, September 16, 1978 6:30 PM - 6:55 PM 7.9M
BBC 1 483. Part Four Saturday, September 23, 1978 6:20 PM - 6:45 PM 8.2M 61%


  • Television Centre Studio 4

Working Titles

The Galactic Con Man

The Ribos File



This story introduces the Key to Time quest that is continued through the season.

John Leeson's K-9 voice is not heard in Part Two.

The organ music heard in the story was played by Leslie Pearson.