11 August (production)


 * 1969 - The Monsters was given a new name — The Silurians — and an extra seventh episode.
 * 1969 - On the same day, assistant script editor Trevor Ray sent a revised version of episode one of The Carriers of Death to script editor Derrick Sherwin, who was unpleased with David Whitaker's work. A meeting was held two days later to discuss the serial.