ALTOS
Played by:- Robin Phillips
and
SABETHA
Played by:- Katharine Schofield
Appeared in:- The Keys of Marinus (5 episodes)
Joined the Doctor and crew in their search for the hidden Keys of Marinus after being freed from the mind-controlling Morphos of Morphoton. Both had been sent to search for the Keys separately by Arbitan. With the Tardis already overcrowded by later standards, they decided to settle in the city of Millenium.

JENNY
Played by:- Ann Davies
Appeared in:- The Dalek Invasion of Earth (5 episodes)
One of the resistance fighters the Doctor and crew met in London, and who accompanied Barbara to the Bedfordshire mine. The character was originally intended to replace Susan on board the Tardis when Pamela Franklin was in line for the part. However, producer Verity Lambert changed her mind, Franklin was dropped and a new companion introduced in the following story.

KATARINA
Played by:- Adrienne Hill
Appeared in:- The Myth Makers & The Dalek Masterplan (5 episodes)
Regarded by many as a fully fledged companion because her appearance overlapped two stories, although in truth she only appeared in a quarter of her first and less than a third of her second. A young Trojan handmaiden who helped Steven back to the Tardis when he was injured in a sword fight, she was then whisked off into a bewildering future. The original idea had been for Katarina to replace Vicki on a permanent basis, but it was realised very early on that someone from the 13th Century BC would be woefully out of their depth, so the idea was scrapped. She became the first companion, full-time or one-off, to die when she sacrificed herself when being held hostage by a hijacker.

SARA KINGDOM
Played by:- Jean Marsh
Appeared in:- The Dalek Masterplan (9 episodes)
The second one-off companion to be regarded as a fully-fledged companion despite only appearing in one story. A security agent sent to kill the so-called traitor Bret Vyon (her brother) and his mysterious accomplices (the Doctor and Steven) when they arrived on Earth. Caught in a transmat beam with the Doctor and Steven and sent to Mira, she realised her mistake and joined forces with the time travellers. Aged to death on Kembel when the Doctor used the Daleks's Time Destructor to destroy their secret base.

ANNE CHAPLETTE
Played by:- Annette Robertson
Appeared in:- The Massacre (4 episodes)
A young Huguenot serving maid who helped Steven survive the hazards of 16th Century Paris. The character was originally intended to be Vicki's replacement but producer John Wiles vetoed the idea on the grounds that someone from the 16th Century would have extreme difficulty relating to modern and future technology. It didn't stop 18th Century Jamie enjoying a long career as a companion later though. Her place on board the Tardis was filled by a character claimed to be a distant descendent.

SAMANTHA BRIGGS
Played by:- Pauline Collins
Appeared in:- The Faceless Ones (5 episodes)
A girl who turned up at Gatwick Airport looking for her missing brother and who quickly found herself helping the Doctor and Jamie uncover the truth behind Chameleon Tours. Samantha was yet another one-off companion originally intended to become full-time. Instead, Collins declined the offer of several months' regular work in order to save herself for future stardom.

CULLY
Played by:- Arthur Cox
Appeared in:- The Dominators (5 episodes)
Joined forces with the Doctor and crew to overcome the Dominators's threat to his planet, the only Dulcian to do so. Unfortunately, official policy at the time decreed that two companions were enough, so he flew Teel and Kando home instead.

ISOBEL WATKINS
Played by:- Sally Faulkner
Appeared in:- The Invasion (8 episodes)
Trendy niece of missing scientist Professor Watkins. Was very much part of the Doctor's entourage in the battle against Tobias Vaughan and his Cybermen allies. Only the promise of a blissful future with Captain Jimmy Turner kept her on Earth.

LIEUTENANT CARSTAIRS
Played by:- David Savile
Appeared in:- The War Games (10 episodes)
One of the many soldiers kidnapped by the War Lords to take part in their war games. A constant companion to the Doctor, Jamie and Zoe throughout all ten episodes, Savile was later rewarded for his efforts by being cast in The Five Doctors.

BELLAL
Played by:- Arnold Yarrow
Appeared in:- Death to the Daleks (4 episodes)
The first alien one-off companion, and the only one to appear with the Doctor's third incarnation. The little Exxilon helped the Doctor overcome the City's seemingly impenetrable defence systems, then stayed behind to help rebuild his planet. His appearance would've been a bit difficult to explain on 20th Century Earth. Severe burns victim...?

CORDO
Played by:- Roy Macready
Appeared in:- The Sun Makers (4 episodes)
Decided not to jump off a roof in order to help the Doctor overthrow the Collector's bureaucratic tyranny. Might have joined Leela as a full-time companion had he not suddenly found so many new friends.

IDAS
Played by:- Norman Tipton
Appeared in:- Underworld (3 episodes)
Refugee Trog scratching an existence in a newly formed planet controlled by the Oracle, a former ship's computer with ideas above its station that was keeping the descendents of the original crew in a permanent state of primitive ignorance. With a background almost identical to Leela's, Idas would have formed half of an unusual partnership had he not decided to stay with his people, all cramped together on a ship that was far too small, on a journey likely to last several lifetimes.

KIMUS
Played by:- David Warwick
Appeared in:- The Pirate Planet (4 episodes)
Impressed the Doctor by speaking out against the Captain's tyrannical rule and thus forced into becoming a rebel. Accompanied the Doctor and Romana on most of their escapades on Zanak but couldn't bring himself to leave girlfriend Mula behind for further adventures in space and time. Quite understandable.

TYSSAN
Played by:- Tim Barlow
Appeared in:- Destiny of the Daleks (4 episodes)
Starship engineer stranded on Skaro. Helped the Doctor stay one step ahead of both the Daleks and the Movellans, though his ulterior motive was to free human prisoners from Dalek capture. Once he'd achieved this objective, he was off back to Earth. A tad too humourless to be a full-time companion.

DUGGAN
Played by:- Tom Chadbon
Appeared in:- City of Death (4 episodes)
Accident-prone private detective who teamed up with the Doctor and Romana to uncover Count Scarlioni's secret identity. The first temporary companion to travel in the Tardis since Sara, yet despite being a carbon-copy of male companions like Ian, Steven, Ben and Harry, has never been regarded as anything more than a single story character. Was left behind on the Eiffel Tower by the Doctor and Romana. A mistake.

RICHARD MACE
Played by:- Michael Robbins
Appeared in:- The Visitation (4 episodes)
Helped the Doctor defeat the Terileptils and their plan to eradicate the population of 17th Century Earth. Maybe if he'd been younger, and the Tardis hadn't already been full, he could have stayed on rather than remaining in London to help fight the Great Fire.

CHELA
Played by:- Jonathon Morris
Appeared in:- Snakedance (4 episodes)
Historical Research assistant who helped the Doctor and Nyssa defeat the Mara on Manussa. More than adequately filled Adric's shoes but was overlooked in favour of the seriously strange Turlough.

WILL CHANDLER
Played by:- Keith Jayne
Appeared in:- The Awakening (2 episodes)
17th Century peasant who was whisked forward into the 20th Century by the Malus. Were it not for the unwritten law which forbade anyone born before 1728 joining the Tardis crew, young Will would have been around for far longer than the one-and-a-half episodes he actually was. It was a real surprise not to see him emerge from the Tardis in Frontios.

HUGO LANG
Played by:- Kevin McNally
Appeared in:- The Twin Dilemma (4 episodes)
Survived crashing his ship on an uninhabited planet, sought refuge in the Tardis and ended up on an alien world whose people promptly chose him as their leader. This was Steven's Doctor Who career condensed into four episodes. Yet another prime candidate for full-time companion status who mysteriously waived the opportunity.

HERBERT
Played by:- David Chandler
Appeared in:- Timelash (2 episodes)
Appeared to be a perfect new companion until his true identity was revealed in the final scene - Herbert George (H.G.) Wells. Not even Doctor Who could get away with featuring a real-life famous writer as a long-term character. Like Duggan, Will Chandler and Hugo Lang before him, travelled in the Tardis but has never been regarded as anything more than just another single story character.

RAY
Played by:- Sara Griffiths
Appeared in:- Delta and the Bannermen (3 episodes)
Young Welsh girl whose childhood sweetheart ran off with an alien queen. Was in line to replace Mel as the Doctor's next companion until (a) the actress originally chosen, Lynn Gardner, was forced to pull out through injury, and (b) Bonnie Langford decided to stay on until the end of Dragonfire. It was a shame because Ray (or Sara) was certainly cuter and more audience-receptive than Mel or Ace ever were. An opportunity missed.

EARL SIGMA
Played by:- Richard D.Sharp
Appeared in:- The Happiness Patrol (3 episodes)
Medical student from Terra Omega who got stranded on Terra Alpha and helped the Doctor introduce the blues. Turned down the chance to become the Doctor's first black companion to help Susan Q convert the Terra Alphans from political repression to clinical depression. At least he'd have had the qualifications to deal with it!

SHOU YUING
Played by:- Ling Tai
Appeared in:- Battlefield (4 episodes)
Archæology student working with Peter Walmsley at the Carbury dig. Avoided being evacuated to link up with Ace in the fight against Morgaine and the Destroyer. Could actually have joined the Doctor and Ace on their travels for a while as there may well be a gap between Battlefield and Ghost Light. One the Missing Adventures missed.