It's about Time

E was a pioneering space explorer, a brilliant scientist but with a knack of getting into all sorts of scrapes. Battling aliens, pterodactyls and erupting volcanoes, Professor Wedgwood was a man ahead of his time.

Along with his equally talented family, the Professor was the hero of Pathfinders, one of the first children's science fiction programmes on television. But the series, broadcast on ITV from 1960-1, was itself to become a pathfinder in a way its creators could never have imagined.

A year after Pathfinders finished, its producer, Sydney Newman, found himself, as head of drama at the BBC, looking for a Saturday tea-time series, to bridge the gap between Grandstand and Juke Box Jury. Recalling his experience of Pathfinders, he turned to science fiction, and Doctor Who was born.

According to a memo while the series was in development, Doctor Who was "a name given to him by his three earthly companions because neither he nor they know who he is. Dr Who is about 650 years old. Frail looking, but wiry and tough like an old turkey".

Accompanied by his granddaughter Susan, the mysterious Doctor roamed through time and space in a craft which was meant to be able to change shape to blend in with its surroundings, but unfortunately, had got stuck in the shape of a police box. The first episode saw them pick up two additional companions, in the shape of Susan's teachers, Ian Chesterton and Barbara Wright.

Initially, Newman intended the series to have an educational thrust, as the time travellers became involved in historical events. But although the Doctor and his companions found themselves among the Aztecs, at the OK Corral, and, in the first ever episode, among cavemen discovering fire, the fact-based stories largely gave way to the more popular monster-oriented tales.

The Doctor was originally played by William Hartnell, a veteran actor previously best-known as the gruff sergeant major in The Army Game. Hartnell's Doctor started out as something of an anti-hero: cantankerous, suspicious and heedless of his companions' safety, not at all the benign protector the role was to later become.

That first series also introduced the world to the Daleks, who rolled into view despite BBC top brass asking that there should be "no bug-eyed monsters" in the new programme. They were an instant success: almost doubling the audience overnight and spawning a merchandising boom. Created by Terry Nation and inspired by the gliding motion of the long-skirted Georgian State Dancers, the Daleks were also to feature in two films made in the 1960s, with Peter Cushing taking the role of the Doctor.

Doctor Who was fast becoming a hit, reaching not just the children who were its target market, but hooking adults too, perhaps partly because it was made by BBC Drama, and never, surprisingly in view of its origins, by the corporation's children's department. But after three years, and in poor health, William Hartnell decided to retire from the role, presenting its producers with the dilemma of how to continue the programme without the lead character.

The inspired solution was to guarantee the longevity of the series which went on to run for a total of 26 years. The Doctor would be regenerated, a previously unmentioned phenomenon which allowed him to swap a tired or injured body for a new one. After his battles against the Cybermen - a new foe although they were to return many times and were to be second in popularity only to the Daleks - took their toll, the Doctor was transformed into the form of Patrick Troughton.

Along with a new face, the Doctor's second incarnation had a new personality. If Hartnell was the grumpy old man, then Troughton was the clown, a Chaplin-esque figure who played the recorder to help him think. His three years in the role saw repeated rematches with both the Daleks and the Cybermen, as well as the introduction of new enemies, in the shape of the Yeti and the Ice Warriors.

Troughton's departure in 1969 filled in a further element of the mysterious Doctor's background. For the first time, his audience became aware that he was a Time Lord, one of a powerful race who had discovered the secret of time travel but had vowed not to interfere in the workings of the universe.

This was to prove the key to the adventures of Troughton's successor, Jon Pertwee. Exiled on Earth because of his meddling, Pertwee's Doctor was unusual in spending little of his time crossing the universe in the Tardis, and instead took to defending his adopted planet from repeated invasions.

Pertwee's Doctor was an action man, versed in Venusian Aikido, a form of karate, and a lover of gadgets, fast cars and even a helicopter. His four years as the man in the velvet coat saw the first appearances of both the Master, another Time Lord and the Doctor's arch-enemy, and UNIT (United Nations Intelligence Taskforce), the military outfit headed by Brigadier Alastair Lethbridge Stewart.

Exhausted by a battle with giant spiders on the planet of Metebelis III, Pertwee's Doctor gave way to Tom Baker, who was to prove the longest-serving and the most popular among many fans. With a long, multi-coloured scarf, floppy hat and pockets full of jelly babies, he was part action man, part clown, but all bravado. The scarf itself was the result of a misunderstanding: the knitter thought she had to use all the wool she had been given. Robot dog K9 became one of the Doctor's "companions" in the Baker era.

Baker's seven years as the Doctor also saw the programme take on a lighter, more comic style, but in 1982 he was succeeded by the less commanding presence of Peter Davison, a John Major to Baker's Thatcher. Dressed as an Edwardian cricketer, and frequently saving the day with a well-aimed cricket ball, Davison's reign also saw the show move away from its Saturday tea-time slot to twice-weekly midweek.

In 1984, Colin Baker took over the role, reversing a trend which had seen the Doctor get younger with each regeneration. Baker was moody and poetic in turn, but the sixth incarnation also saw declining ratings, leading the BBC to announce it was resting the show, in February 1985.

Fan outrage brought it back the following year, but the Doctor was on trial and Baker was replaced by Sylvester McCoy. Initially, McCoy's Doctor was a juggling entertainer, before moving into darker territory, but after just two years in the role, the programme was "rested", and this time it seemed permanent. It had run for 26 years and was watched around the world, but it was judged that its time was past.

And there it lay for 14 years, apart from the 1996 TV film with Paul McGann in the title role, until BBC1 Controller Lorraine Heggesey announced, in 2003, that it was coming back to Saturday evenings.

Written by Russell T Davies, the man responsible for Queer As Folk and Bob and Rose, and with Christopher Eccleston as the (ninth) Doctor, the new series will pit the Time Lord against old foes, including the Daleks and the Autons, plastic villains encountered in two Pertwee stories from the 1970s, as well as new ones. It may have been a long wait, but for the fans the Doctor's return is about time.