The Companions

Debut

Susan Foreman, Barbara Wright and Ian Chesterton

Carole Ann Ford, Jacqueline Hill and William Russell. Two schoolteachers worried about a pupil follow her home and are, in plain terms, abducted — the Doctor takes off rather than let them leave and talk. Ian and Barbara spend two years trying to get back to 1963, and the early show's real moral centre is Barbara, who argues with him and usually wins.

Susan is the only companion in the programme's history who is the Doctor's own family — a granddaughter whose exact origins the series has never explained.

Departure

Susan is locked out

On a ruined 22nd-century Earth the Doctor decides his granddaughter has outgrown him, shuts the TARDIS doors from the inside and leaves her there. Hartnell's farewell speech is the first companion exit and still the template for all of them: it is about the Doctor's own inability to stay anywhere.

Death

Katarina, and then Sara Kingdom

A handmaiden from the fall of Troy who believes she has died and is being conducted through the afterlife, and who blows herself out of an airlock to save the ship. Adrienne Hill lasted five episodes. Weeks later Jean Marsh's Sara Kingdom is aged to dust in the same serial.

The first companion deaths in the programme, two years into its run — and for twenty-five years, almost the only ones.

Debut

Jamie McCrimmon

Frazer Hines, as a piper from the rout at Culloden, written in for one serial and kept for three years because the chemistry with Troughton was immediate. He appears in more episodes than any other classic companion, and the Doctor–Jamie partnership is the first the show treats as a real friendship between equals rather than a teacher and a pupil.

Longest-serving companion of the classic series: 116 episodes across six seasons.

Departure

Jamie and Zoe are sent home, minus the memories

The Time Lords return them to the moments they were taken from, with everything after erased except the first adventure. It is the cruellest companion exit the show has written: not a goodbye but a deletion, and the two of them walk away mid-conversation without knowing who they have lost.

Debut

Sarah Jane Smith

Elisabeth Sladen, as an investigative journalist who talks her way into a research facility on a forged pass and is furious about being patronised. She is the companion the programme keeps coming back to: three and a half years with two Doctors, a spin-off pilot in 1981, a return in 2006, and five series of her own children's show from 2007 until Sladen's death in 2011.

More screen time across more decades than any other companion, and the only one to headline two spin-offs.

Debut

Leela

Louise Jameson, as a warrior exiled from a tribe descended from a crashed survey team — introduced killing people with a knife and never really persuaded to stop. The intended dynamic was Pygmalion, and what makes it work is that Leela is not stupid, merely unschooled, and frequently right when the Doctor is being clever.

Debut

Romana

Mary Tamm, as a Time Lady assigned to the Doctor by the White Guardian, with a triple first and no field experience whatsoever. For the first time the companion is his equal in origin and his superior on paper, and the show has to find its comedy somewhere other than explaining things.

Regeneration

Romana regenerates — by choice

Lalla Ward takes over in a scene where Romana tries on several bodies like coats before settling on one, purely because she liked it. It is the only time the series has shown a Time Lord regenerating electively — and it quietly establishes, in 1979, that the process has nothing necessarily to do with dying.

Death

Adric dies

Locked on a freighter falling into prehistoric Earth, working on a logic puzzle he does not solve in time. The Doctor does not save him and cannot go back. The closing credits run in complete silence over his shattered star badge — the only time in the programme's history the theme has not played.

The first companion death in seventeen years, and the last for twenty-six.

Debut

Ace

Sophie Aldred, as a teenager from Perivale blown across the galaxy by a time storm she caused herself, carrying a rucksack of home-made explosives and a great deal of unexamined anger. The Cartmel era gives her the first real psychological arc any companion has had — and then has the Doctor deliberately engineer situations that force her through it, which is not obviously a kind thing to do.

The prototype for every revival companion: a working- class contemporary with a life and a family that the show keeps returning to.

Debut

Rose Tyler

Billie Piper, nineteen, working in a Hendrik's department store with no A-levels and a boyfriend she is bored of. Russell T Davies's central structural decision is that the revival's first episode is hers — the Doctor is a supporting character in it, glimpsed and investigated, and the audience learns about him only as fast as she does.

The revival also does something the classic series never did: it shows where the companion came from, and keeps her mother and her boyfriend in the programme.

Debut

Captain Jack Harkness

John Barrowman, as a Time Agent turned con man who flirts with everyone regardless of species or gender — the first openly queer companion in the show's history, introduced without a single line of justification. Killed and resurrected as an immortal at the end of the season, and given his own series the following year.

Debut

Martha Jones

Freema Agyeman, a final-year medical student who keeps her head while a hospital is teleported to the moon, and the first Black companion in the programme's history. Her season saddles her with unrequited feelings for a man still grieving someone else — and her exit is the reason she matters: she walks out, tells him exactly why, and goes back to her family and her career.

The first companion to leave for her own reasons and on her own schedule, rather than being killed, stranded or wiped.

Return

Donna, properly

Brought back full-time as the only companion of the revival with no romantic interest in the Doctor at all — a friendship of equals in which she is repeatedly the one who tells him he has gone too far. Her ending is the cruellest the modern show has written: to save the universe she absorbs his mind, and to save her life he removes every memory of him.

Debut

River Song

Alex Kingston, introduced already knowing him and dying at the end of her first appearance. Their timelines run in opposite directions, so every subsequent meeting takes her further back towards a first encounter that, for her, has already happened. The most structurally ambitious character the programme has attempted.

Debut

Amy Pond

Karen Gillan, met first as a seven-year-old with a crack in her bedroom wall, promised he would be back in five minutes, and collected twelve years later on the night before her wedding. Steven Moffat builds the whole era on the premise that the Doctor is a story a child was told and then had to grow up around.

Debut

Clara Oswald

Jenna Coleman is introduced, killed, reintroduced at Christmas and killed again before joining properly in 2013 — because the mystery of why she keeps appearing throughout the Doctor's timeline is the season's plot. Later she becomes something the show had not tried: a companion who starts copying him, takes his risks, and dies for it.

Debut

Bill Potts

Pearl Mackie, serving chips in a university canteen and attending lectures she is not enrolled in, which is how the Doctor notices her. The first openly gay companion, established in her opening scene as a matter of character rather than announcement. Her season restores something the show had drifted from: a companion who asks obvious questions and is respected for it.

Debut

Ryan Sinclair, Yasmin Khan and Graham O'Brien

Tosin Cole, Mandip Gill and Bradley Walsh: a warehouse worker with dyspraxia, a probationary police officer, and a retired bus driver in remission from cancer who is Ryan's step-grandfather. The first three-companion TARDIS team since 1982, and the first built as a family that already exists before the Doctor turns up.

Yasmin Khan goes on to serve four series — the longest continuous run of any revival companion.

Debut

Ruby Sunday

Millie Gibson, left as a baby on the steps of a church on Ruby Road on Christmas Eve and raised in foster care — with the identity of her birth mother running as the season's central mystery. The answer, when it comes, is deliberately mundane: she was a frightened nineteen-year-old and nothing more, and the universe made her matter only because everyone was looking.