An Earth colony in the far future has all the look and feel of a holiday camp. But the Doctor, Polly, Ben and Jamie quickly become aware that a sinister force is lurking beneath the jolly veneer of the settlement, in the form of the mammoth crab-like Macra who have secretly infiltrated the colony administration and are using the settlers for slave labour. And already, Ben has fallen into the Macra's power.

Writer Ian Stuart Black had penned back-to-back tales for Doctor Who's third season -- The Savages and The War Machines -- in early 1966. In November of the same year, story editor Gerry Davis asked Black to submit a new idea, indicating he wanted a holiday camp setting involving monsters living under the earth. Both Black and Davis wanted to avoid reusing old monster concepts, and after reviewing the roster of Doctor Who stories to date, they settled on a spider-type creature as something the programme had not yet attempted. Black was duly commissioned to write “The Spidermen” on December 11th, 1966. The title would acquire an exclamation mark later in the month.

Black's original drafts differed from the finished scripts in a few respects. Most notably, in part two, the Doctor was originally sent to the House of (rather than “Hospital for”) Correction alongside Medok, and it was after the brainwashing attempts there fail that he was sent to the pithead. Also, the Pilot at this stage was referred to as the Prime Minister and Medok was spelled “Medoc”. Black departed somewhat from the original arachnid vision of the monsters, describing them as general insectoid creatures, and the serial's title became “The Insect-Men” to reflect this. Davis feared that the result might hew rather too closely to the Zarbi from Season Two's The Web Planet, however, and indicated that the monsters should instead be giant crabs. They were thus dubbed “Macras”, apparently from the genus name of the Japanese spider crab, macrocheira kaempferi. Unfortunately, some dialogue references to the Macra as “insects” survived in Black's final draft and were present upon transmission. The title was changed to “The Macras” and then, finally, to The Macra Terror in late January 1967.

Anneke Wills, meanwhile, was contracted for The Macra Terror -- Serial JJ -- and the ensuing eight episodes (covering two further four-part stories) on December 12th. In the weeks that followed, Davis and producer Innes Lloyd elected to write Polly and Ben out of Doctor Who, feeling that their characters were not working as well as they had hoped. Furthermore, on January 2nd, Serial KK was expanded from four episodes to six to accommodate The Faceless Ones, meaning that Wills' contract now expired with part two of the next adventure, The Evil Of The Daleks. Lloyd and Davis therefore planned for Ben and Polly's exit to occur mid-serial, and so Michael Craze's contract renewal on January 27th also secured his services only until The Evil Of The Daleks episode two. Frazer Hines, meanwhile, had had his option on The Macra Terror taken up on the 16th.

The director assigned to The Macra Terror was John Davies, his only work on Doctor Who. To date, Davies had worked on episodes of programmes including United! and The Newcomers; he would subsequently earn credits for everything from Tales Of The Unexpected to Miss Marple. Davies began production on February 15th with location filming at an Associated Portland Cement Manufacturers Ltd quarry at Dunstable in Bedfordshire. This involved the opening sequences in which the Colony guards chase Medok and the TARDIS materialises. A 16mm handheld camera was used in addition to the standard 35mm stationary camera. Filming at the Ealing Television Film Studios occurred on the 17th for the scenes involving the Controller. Davies also recorded a shot of a Macra claw which would be seen on the TARDIS scanner at the end of part four of The Moonbase, the serial preceding The Macra Terror.

Meanwhile, Lloyd had for some time been contemplating revamping the opening Doctor Who title sequence, which had not been changed since the show's debut in November 1963. The services of Bernard Lodge, who had designed the original version, were once again secured. Lodge recalled that during test filming in 1963, he had stood in front of the camera and his visage had become incorporated into the electronic effect. Then-producer Verity Lambert had feared that the technique was too scary and forbade its use at the time. Lloyd, however, liked the concept and agreed that a photocaption of Patrick Troughton's face should be used for the new credits; this would become a hallmark of all future Doctor Who opening sequences. Lodge and engineer Ben Palmer created the new titles in early December. Lloyd considered introducing them with The Underwater Menace but eventually elected to hold them back for two serials until episode one of The Macra Terror.

This selfsame installment went into the studio on March 4th: Doctor Who episodes were now recorded each Saturday in Lime Grove D. Wills debuted a new, shorter haircut on this day; allowance was made for it in the narrative, in which it was part of Polly's refreshment regimen at the Colony. Wills wore hair extensions for the first few scenes of the story as a result. The full-sized Macra prop was unveiled on the same day. The unfeasibly large prop, almost ten feet tall, needed to be mounted on a van in order to be moved, and was therefore very awkward to manipulate in the studio.

Only one Macra constructed for the serial. Consequently, when recording the part three scene, on March 18th, where Jamie appears to be menaced by two of the monsters, Davies was forced to employ out-of-sequence recording. All the scenes involving the Macra moving from right to left were taped first, followed by those in which the “other” Macra moves from the left to the right.

The recording of episode four on March 25th completed production on The Macra Terror. Unusually, this saw the role of Chicki recast because actress Sandra Bryant, who had played the part in episode one, had asked to be released from her contract. Lloyd agreed to this request on March 10th, and Karol Keyes replaced Bryant for the fourth installment.

The Macra Terror was Black's final televised contribution to Doctor Who. In the early Seventies, Black submitted a story called “The Space War” (or “The Furies”) to the production office, but this went unmade. Thereafter, Black continued to write for series such as The Champions and, from the mid-Seventies, turned his attention to novels. He also novelised his three Doctor Who stories in the late Eighties. Ian Stuart Black died on October 13th, 1997.

• Doctor Who: The Handbook: The Second Doctor by David J Howe, Mark Stammers and Stephen James Walker (1997), Virgin Publishing, ISBN 0 426 20516 2.
• Doctor Who: The Sixties by David J Howe, Mark Stammers and Stephen James Walker (1992), Virgin Publishing, ISBN 1 85227 420 4.
• Doctor Who Magazine #308, 19th September 2001, “Archive: The Macra Terror” by Andrew Pixley, Panini Publishing Ltd.
• Doctor Who Magazine Special Edition #4, 4th June 2003, “Good Vibrations” by Andrew Pixley, Panini Publishing Ltd.