The newly-regenerated Doctor is exiled to modern-day Earth by the Time Lords, where he becomes attached to the British branch of UNIT as their scientific adviser, ostensibly taking orders from Brigadier Lethbridge-Stewart. The Doctor's first task is to investigate a shower of strange plastic meteorites which landed in the countryside. Nearby, a dollmaker named Ransome discovers that his plastics factory has been taken over by a mysterious man called Channing. Now its corridors are stalked by deadly animated mannequins called Autons, who are determined to recover the last of the meteorites.

More than a year before Doctor Who's seventh season entered production, there was little doubt that it would be very different from its six predecessors. During the summer of 1968, producers Peter Bryant and Derrick Sherwin discussed revamping the programme's format to concentrate on stories set on modern-day or near-future Earth. Earlier that year, they had been very pleased with The Web Of Fear, in which the Doctor worked with the British military against alien invaders in the London Underground. The producers felt that viewers had grown tired of outer space adventures, and they believed that the proposed change to the status quo would make better use of Doctor Who's limited budget. To this end, Sherwin wrote The Invasion for the early part of Season Six. There he established the paramilitary organisation UNIT -- the United Nations Intelligence Taskforce -- led by Brigadier Lethbridge-Stewart, a character whom Nicholas Courtney had originated in The Web Of Fear. When The Invasion was deemed a success, Bryant and Sherwin agreed that Season Seven would see the Doctor trapped on Earth and working with UNIT.

Around the start of 1969, however, the BBC considered cancelling Doctor Who altogether. The programme's ratings had been dwindling in recent months, and it was now known that Season Six would be Patrick Troughton's last as the Second Doctor. During the early months of the year, some thought was given to replacing Doctor Who with a revival of Nigel Kneale's Quatermass serials, or with adaptations of the works of Jules Verne. By the spring, however, it was agreed that Doctor Who should continue for another year, with the new format given the green light to proceed.

It was hoped that Wendy Padbury might remain as Zoe Heriot for a second season

In January, Sherwin reached an agreement with Lethbridge-Stewart's creators, Mervyn Haisman and Henry Lincoln, for the use of the character on an ongoing basis. Although it was known that Frazer Hines, who played companion Jamie McCrimmon, would be leaving alongside Troughton, it was hoped that Wendy Padbury might remain as Zoe Heriot for a second season. However, when Padbury declined the offer of another year on Doctor Who, the production team started to plan for a new female companion. Some thought was given to bringing back photographer Isobel Watkins, whom Sally Faulkner had played in The Invasion. Ultimately, however, it was decided to create a new character. This would be a scientist named Liz, who was developed by Sherwin with input from script editor Terrance Dicks, and who was envisaged as being more mature and intelligent than most previous companions.

The changes to Doctor Who would not be limited to matters of cast or scenario. BBC1 was scheduled to begin transmitting in colour from November 1969, and so Season Seven would see Doctor Who broadcast in colour for the first time. It would also be comprised of far fewer episodes than in the past, since it was planned that Doctor Who would now run for only six months of the year instead of ten. One of Troughton's major complaints about his tenure on the programme had been the exhausting production schedule, and it was felt that the reduced episode count would ameliorate the situation. Because of these factors, Season Seven's debut was scheduled to take place after New Year 1970 rather than the preceding autumn as usual.

To write the adventure which would effectively relaunch Doctor Who, Dicks turned to Robert Holmes, who had recently written both The Krotons and The Space Pirates for Season Six. Since an alien invasion story was a natural fit for the Earthbound format, Holmes, Sherwin and Dicks conceived a creature which would travel through space in distinct segments, requiring its reassembly when it reached the world it planned to conquer. They decided to marry this notion to Sherwin's discomfort with the emerging technology of plastics; it was the producer who observed the eerie quality of shop window dummies, and who also suggested that a doll factory would make a suitably creepy setting. On February 12th, Holmes was commissioned to provide a storyline under the title “Facsimile”.

Holmes' storyline underwent various changes. In Episode One, the Doctor was originally kidnapped from his bed and taken to a storeroom for interrogation; he escaped through a window after feigning unconsciousness. The Autons were defeated by a high-frequency sound which Liz arranged to have transmitted from BBC Broadcasting House. For a time, the poacher, Sam Seeley, was accompanied by a son. Liz's surname was revised from Shore to Shaw, while Captain Munro's last name was originally spelt “Monro”. The scripts for “Facsimile” were commissioned on June 3rd. Later that month, the title was amended to Spearhead From Space.

On July 28th, Caroline John was contracted to play Liz in two serials

Meanwhile, the production team was beginning to assemble a new regular cast. On May 21st, Jon Pertwee agreed to play the Third Doctor. Nicholas Courtney, who had already indicated his interest in reprising Lethbridge-Stewart during the making of The Invasion, was contracted on May 27th. Both actors were booked to appear in at least twenty-one episodes. Casting for the role of Liz occurred during July. Photos of actress Caroline John were forwarded to Bryant and Sherwin by director James Cellan Jones and, on July 28th, John was contracted for the first two serials of the season. The new castmember was revealed to the press on September 10th. John was initially very keen to read up on the scientific terminology she'd be spouting in Doctor Who, and was subsequently dismayed to discover that most of it was invented gibberish.

Over the summer, Pertwee's take on the Doctor was gradually developed, with the actor receiving considerable feedback from his old friend, Shaun Sutton, who was now the BBC's Head of Drama. Although Bryant had intended Pertwee to portray the role in a comedic vein, the actor opted for a more serious approach, with Sutton advising Pertwee to basically play the Doctor as himself. For his costume, Pertwee suggested a high-collared black or white outfit in the style of Pandit Nehru, the first Prime Minister of India. However, Sherwin preferred something less stylised and so, for a publicity photo session, the new leading man half-seriously donned a velvet smoking jacket, a frilly shirt and his grandfather's Inverness cape. To Pertwee's surprise, it was agreed that this was a suitable look for his Doctor; costume designer Christine Rawlins also drew upon the Edwardian aesthetic of the adventure series Adam Adamant Lives!.

With the change of Doctor and the move to colour, it was decided that a new title sequence was needed for Doctor Who. Graphics designer Bernard Lodge, who had originated the first two title sequences, was once again pressed into service. His original plan was to use the same “howl-around” technique he had employed for his two earlier efforts, but he found the colour results disappointing compared to what he had achieved in monochrome. With engineer Ben Palmer, Lodge instead decided to film shifting diamond patterns in black-and-white, then tint them with colour gels using an optical printer. Finally, Pertwee's face and a new Doctor Who logo were added to the mix. One abandoned element was the suggestion that the sequence could begin with Pertwee throwing his cape over the screen, such that the colour patterns then emerged from the resulting darkness. The title sequence was filmed on August 3rd at BBC Television Centre Studio 5 in White City, London. For the first time, an end credit sequence was also created; to date, Doctor Who's closing credits had typically run over a simple black background.

Bernard Lodge found the colour results of the “howl-around” technique disappointing compared to monochrome

The director assigned to Spearhead From Space was Derek Martinus, who had last worked on 1967's The Ice Warriors. This would be his sixth and final Doctor Who serial. Location filming began on September 13th, with the Favourite Doll Factory in Holloway, London providing the Auto Plastics factory floor. The same day, Liz was driven through St Pancras, London along Euston Road and Midlands Road before arriving at UNIT headquarters -- really the National Car Park at St Pancras Station. Cast as the UNIT attendant in this material was Geoff Brighty but, during recording, he was found to be unsuitable for the part. Derrick Sherwin himself, a former actor, stepped into the role.

September 14th was devoted to the activation of the Autons along the Broadway in Ealing, London. Careful camera angles and sound effects ensured that no glass need actually be broken. On the 15th and 16th, land owned by the Royal Horticultural Society in Wisley, Surrey served as Oxley Woods. Hatchford Park School in Hatchford, Surrey was used as the grounds of Ashbridge Hospital on September 17th. Finally, on the 18th and 19th, more Auto Plastics material was filmed at the former premises of TCC Condensers in Acton, London -- a property now owned by the BBC. While there, assistant script editor Robin Squire was pressed into service as an Auton when the original performer suffered an attack of claustrophobia in the close-fitting mask.

Studio recording was then supposed to begin at Television Centre on Monday, October 13th for Episode One, followed by three consecutive Thursdays -- October 23rd and 30th, and finally November 6th -- for the remaining installments. However, since May, the BBC had been involved in an escalating dispute with the Association of Broadcast Staff, with the union complaining of insufficient pay raises accompanying the move to colour transmission. During September, Sherwin became increasingly concerned that industrial action would impact work at Television Centre, thereby threatening his season premiere. He and Bryant discussed possible alternatives and, finally, Sherwin approached his BBC bosses with a proposal to make Spearhead From Space entirely on film -- something never before attempted on Doctor Who. Approval for the plan was granted on September 25th; Sherwin's foresight was vindicated when ABS job action severely curtailed recording at Television Centre from October 12th.

With Sherwin's contingency plan in effect, work on Spearhead From Space resumed on October 8th. The majority of the additional filming took place at the BBC's Engineering Training Centre at Wood Norton, an estate near Evesham, Worcestershire that was once the home of Philippe, Duke of Orléans and claimant to the French throne. Wood Norton was used for various settings, including the tracking station, Ashbridge Hospital, UNIT headquarters, and the Auto Plastics office. Cast and crew were stationed there through to October 28th, with only a handful of exceptions. The 18th and 19th were both days off. On October 23rd, Wheelbarrow Castle Cottage in Radford, Worcestershire was used for Seeley's home. Part of the 28th was also spent at the Mansion House Hotel in Evesham, for material in Scobie's residence.

Meanwhile, Bryant had been shifted off of Doctor Who onto the mystery series Paul Temple, a high-profile but troubled German co-production. Having had time to assess the state of the programme, Bryant informed the BBC that he would need assistance, and asked for both Sherwin and assistant script editor Trevor Ray to join him. With Doctor Who's production team abruptly depleted, Shaun Sutton asked director Douglas Camfield, who had most recently worked on The Invasion, to take over as producer. When Camfield declined, Sutton instead approached Barry Letts, who had directed 1967's The Enemy Of The World. At that time, Letts had suggested a number of changes to the way Doctor Who was being made, some of which Bryant and Sherwin had since implemented. Letts' appointment was made official on October 20th.

With the Worcestershire leg of the production having concluded, Martinus and his team next recorded sequences in London from October 29th to 31st. On November 3rd and 4th, material in the UNIT tent was completed at Van Arden Studios in Ealing on November 3rd and 4th. Cast and crew then spent the evening of November 5th at the famous Madame Tussauds wax museum in Marylebone, London. Additional work in London on the 7th saw the filming of reaction shots to the Auton invasion. Model shots were completed at the BBC Television Film Studios in Ealing on November 19th. By this time, Letts had viewed the footage of the Nestene creature which had been recorded at Wood Norton and decided, in consultation with Bryant and Sherwin, that it would have to be remounted. This additional work took place at Ealing on November 22nd.

Facilitated by the fact that it was made entirely on film, Spearhead From Space underwent substantially more editing than any previous Doctor Who serial, although no significant narrative elements were lost or altered. It also meant that composer Dudley Simpson was able to tailor his incidental music to the action, rather than recording the score in advance so that it could be played into the studio.

Likewise unprecedented in Doctor Who history was the twenty-seven week gap between the end of Season Six and the start of Season Seven. In the interim, the timeslot was principally filled by a science-fiction import from the United States by the name of Star Trek. When Spearhead From Space Episode One aired on January 3rd, 1970, it formed part of a revised BBC1 Saturday evening schedule. Doctor Who was still preceded by Grandstand, but it now led into a new American sitcom, The Debbie Reynolds Show. Spearhead From Space immediately attracted roughly twice the number of viewers who had watched The War Games. But although this was a promising start for the Pertwee era, it remained to be seen whether audiences would embrace so many changes to a programme which had already been running for more than half a decade...

• Doctor Who Magazine #181, 25th December 1991, “Archive: Spearhead From Space” by Andrew Pixley, Marvel Comics UK Ltd.
• Doctor Who Magazine Special Edition #2, 5th September 2002, “Instant Karma” by Andrew Pixley, Panini Publishing Ltd.
• Doctor Who: The Complete History #15, 2016, “Story 51: Spearhead From Space”, edited by John Ainsworth, Hachette Partworks Ltd.
• Doctor Who: The Handbook: The Third Doctor by David J Howe and Stephen James Walker (1996), Virgin Publishing.
• Doctor Who: The Seventies by David J Howe, Mark Stammers and Stephen James Walker (1994), Virgin Publishing.