She worked long hours with the Doctor, whether it was building devices to try and defeat plastic Autons, finding a suitable vaccine against the Silurians' epidemic, or being held hostage by the kidnappers of alien ambassadors.

One sad thing about Liz was that she never got the chance to travel in the Tardis - although viewers saw her on another world. And yet, while it was Liz on that parallel Earth it was someone different. Inferno was Caroline John's last story as Liz Shaw until 1983. She remains one of only three companions who never got any kind of farewell scene.

It was where women were concerned that the Brigadier failed. He had a blinkered naiveté where they were concerned. All the Doctor's assistants were called Miss Shaw, Miss Grant or Miss Smith. He never allowed himself to get on first name terms with them. But the best example of this naiveté came in Planet of the Spiders:

The Brigadier and the Doctor were in a cheap and nasty theatre (in the line of duty). The Brig looked decidedly glum until the "exotic Turkish delight" came on. Should Doris be worried? Not really!

"Extraordinary muscular control," he comments. "I must adapt some of these movements for men."

"It would take some adapting!" quips the Doctor, but his pun falls on deaf ears.

Another of Lethbridge-Stewarts main characteristics was his reluctance to accept the unfamiliar. It is somewhat ironic therefore that this man was entrusted with protecting Queen and country from alien invasion!

The Brigadier on his own at the United Nations Intelligence Taskforce(UNIT) would hardly have been credible so in came Benton, the perfect example of the "Yes Sir" soldier; there to take orders and do a bit of fighting. Having said that, Sergeant Benton did have his moments. For instance, when in The Mind of Evil he is given special responsibilities in looking after a prison, he answers a telephone call with "Acting Governor Benton?" And during the Invasion of the Dinosaurs Benton had to overpower the traitorous General Finch. Threatened with court martial, Benton apologised profusely and then punched him on the nose!

But it wasn't really until the beginning of the next season that the UNIT family fell into place. The Brig, Liz, and Benton had already been introduced, then as Liz went back to Cambridge, Terror of the Autonswas to introduce Captain Mike Yates and Jo Grant; and if there is a blacksheep in every family then the Master was surely that in this one. As for the Doctor, he was less like the Grandfather of old and more like the mother hen of them all!

Jo got into UNIT when a high ranking relative pulled some strings. Although trained in espionage, this scatty, excitable girl was rather accident-prone; so the Brigadier foisted her onto the Doctor. Unlike Liz Shaw, Jo was not academically bright but she certainly had her marbles when it came to getting on with things. But she was frequently idiotic, and this meant she was forever getting herself into scrapes. Despite this, the Doctor warmed to her loyalty, enthusiasm and youthful breeziness.

Mike Yates was a more complex character though it was much later before this complexity was explored. Suffice to say for now that Yates was a military man, between the Brigadier and Benton in rank. He was an intelligent perfectionist: an elegant man looking for a perfect world ...

The final member of this illustrious "family" to be introduced in Terror of the Autons was the Master, as portrayed by Roger Delgado. Delgado was a dark and strikingly handsome man who played with great panache the sinister scientist, versed in all the black arts, who repeatedly plots to do down the Doctor. Though entirely convincing in his sudden machiavellian appearances and disappearances and his blood-curdling threats of disaster for the Doctor, he was a villain whom it was hard to hate.

Delgado was killed in a car crash in Turkey during the making of a film. He last appeared in "Frontier in Space" on 31^st March 1973, when his success in the role lead to suggestions that his popularity even overshadowed that of the Doctor.

Delgado's death had a great impact on the cast; and one by one the rest of the "family" left.

In The Green Death Jo found someone not unlike the Doctor in Clifford Jones, but he was more in her age group. He was a man who promised her a slightly freakish lifestyle and plenty of high-jinks. Just right for Jo.

It was in the Invasion of the Dinosaurs that Mike Yates began to evolve further than most viewers would have expected. Operation Golden Age appealed to Yate's idealistic side; so much so that he betrayed his UNIT colleagues. He wasn't so much a traitor as a misguided idealist. After this Yates was given extended sick-leave and a chance to resign quietly. However this was not the last we were to see of Mike Yates.

Mike had made a close friendship with Jo's replacement, a young journalist by the name of Sarah Jane Smith. In Planet of the Spidershe leads Sarah to his Buddhist retreat where he is worried by the chanting, but this proves to be the last we see of the character.