The quest for the third segment of the Key To Time takes the TARDIS to modern-day Earth, near a stone circle called the Nine Maidens. A druidic cult led by the sinister De Vries is performing blood rituals there, honouring a Celtic goddess called the Cailleach. At the same time, archaeologist Emilia Rumford and her assistant, Vivien Fay, are investigating strange flaws in previous surveys of the circle. Left alone at the Nine Maidens, Romana is nearly driven over a cliff by an apparition which takes the Doctor's form. Meanwhile, the Doctor discovers that the megaliths are actually monstrous Ogri, in service to an ancient villain...

For more than 2500 years from the late Neolithic period, the peoples of the British Isles and Brittany constructed stone circles, also known as cycloliths. Their original purpose became lost to history, although it's generally believed that the majority were constructed for ceremonial reasons. The most famous example is Stonehenge, on Salisbury Plain in Wiltshire, but more than a thousand other circles are known to exist, and these may represent as a few as one-third of the total number which once stood. In many cases, various legends became associated with the cycloliths over time, such as reports of stones moving around the countryside, and the belief that two observers would obtain different tallies if they tried to count the number of stones in some circles.

Amongst those fascinated with the mythology of the cycloliths was writer David Fisher. In 1963, he had unsuccessfully proposed a storyline based around Stonehenge for Doctor Who's very first season. Then, in 1977, Fisher was amongst the writers new to Doctor Who whom script editor Anthony Read approached as he developed the programme's sixteenth season. Since Read was looking for a story idea with supernatural overtones, Fisher decided to return to the theme of the stone circles and related folklore. He was also asked to include strong female characters in his storyline, which was commissioned under the title “The Nine Maidens” on December 8th, 1977.

The Stones Of Blood was positioned third in the season, so it would be broadcast around Hallowe'en

Around the start of 1978, Read and producer Graham Williams decided that every serial of Season Sixteen would be given a title of the form “The [Something] Of Time”, in order to emphasise the linking Key To Time story arc. As such, when Fisher's full scripts were commissioned on January 10th, they became known as “The Stones Of Time”. This idea was subsequently abandoned, however; by the end of March, the scripts carried the title The Stones Of Blood. Fisher's adventure was positioned third in the season, in order to ensure that it would be broadcast around Hallowe'en.

Fisher included several allusions to British mythology in The Stones Of Blood. Vivien Fay and her earlier alias, Lady Morgana Montcalm, recalled Morgan le Fay, King Arthur's sorceress half-sister in the legends of Camelot. The word “cailleach” was a Gaelic term meaning “old woman”, and was associated with several entities in Celtic mythology. The Ogri were named after the ogres, fearsome monsters found in a variety of fairytales. The reference to Dr Thomas Borlase was an homage to two celebrated historians, Thomas Price and William Borlase. The Megara referred to Megaera, one of the Furies of Greco-Roman mythology. Also called the Erinyes or Eumenides, they were goddesses who persecuted those they perceived as guilty of a terrible crime. Two names were modified during scripting: Leonard De Vries (whose surname alluded to American satirist Peter De Vries) was originally called Charles, while the stone circle at the heart of the tale became the Nine Travellers, rather than the Nine Maidens.

The director assigned to The Stones Of Blood was Darrol Blake. This would be his only credited Doctor Who serial, although he had been a design assistant on Marco Polo in 1964. Blake decided to make a significant change to Fisher's conception of the Ogri, which the writer had envisaged as rocky-skinned humanoids who looked like megaliths only when stationary. To save costs, Blake elected to have the Ogri appear as huge stones throughout, although elements of Fisher's original idea -- such as the large footprint found by the Doctor and Romana -- remained in the script. The simpler design requirements freed up room in the budget to add the Episode Three sequence involving the two ill-fated campers. This material served an additional purpose by illustrating the revised conception of how the Ogri killed their victims: instead of merely crushing people, the monsters would now absorb their blood. The Megara were also altered from the flying metal orbs depicted by Fisher. Blake felt that this image was too similar to the training remote used by Luke Skywalker for lightsaber practice in the 1977 blockbuster film Star Wars, and so the Megara became floating lights instead.

On May 15th, John Leeson was contracted to provide the voice of K·9 in The Stones Of Blood. Three days later, Mary Tamm's contract was extended to cover the final four serials of Season Sixteen. For a while, the production team had considered the possibility of Romana regenerating multiple times during the quest for the Key To Time, with new actresses joining the series opposite Tom Baker; this notion had now been dropped.

Location recording for The Stones Of Blood began on June 12th at the Reed College of Accountancy in Little Compton, Warwickshire. One of the buildings on its campus, dubbed the Manor, featured as the exterior of De Vries' house. The next day, the Nine Travellers were represented by an authentic cyclolith called the King's Men. Dating from the early Bronze Age, it was reputed to have been formed when an army was turned to stone by a witch. Standing near Little Rollright, Oxfordshire, the King's Men formed part of a complex of monuments known as the Rollright Stones, which also included the solitary King's Stone and a smaller group of megaliths known as the Whispering Knights. During a break in filming, cast and crew were joined by a group of children who were tasked with counting the King's Men as part of a school assignment. The students were baffled when their tally reached eighty stones, rather than the anticipated seventy-seven... until it was revealed that they had inadvertently included the Ogri props.

When Blake's team arrived in Little Rollright for filming on the morning of June 14th, they discovered that the TARDIS prop had been stolen by students from Reed College. Fortunately, it was soon found hidden nearby. Work on this day began with scenes on the moorland, recorded on the grounds of the Manor Farm. The remainder of the 14th and all of the 15th were then spent at Little Rollright Quarry for the material on the cliffs. Tom Baker refused to appear on camera for the scene where the Doctor's apparition forced Romana off the precipice, since he was concerned that it would shake younger viewers' trust in him. Blake agreed to frame his shots so that only the Doctor's voice would be heard.

The remainder of The Stones Of Blood was recorded at BBC Television Centre Studio 3 in White City, London. Work there began with a two-day session on July 3rd and 4th. Since there had been no provision for night shooting on location, the first day was dedicated to nocturnal scenes at the Nine Travellers, plus the campers' demise. The second day dealt with sequences in De Vries' house, as well as on the clifftop.

The Stones Of Blood would be the 100th Doctor Who serial

By now, it had been realised that The Stones Of Blood would be the one hundredth Doctor Who serial; furthermore, its transmission would closely coincide with the programme's fifteenth anniversary on November 23rd. Because Episode One was underrunning, it was agreed that an extra scene would be added in which Romana and K·9 celebrated the Doctor's 751st birthday, complete with a cake and a present: a new scarf, identical to the one the Doctor was already wearing. However, Fisher was concerned about the skit's irrelevance to his narrative, while Williams and Read ultimately decided that it was too self-congratulatory. The producer was also keen to avoid hinting at the topic of Gallifreyan procreation. The sequence was dropped, with Williams instead scripting the White Guardian's warning and the Doctor and Romana's ensuing discussion, providing a recap of the season-long story arc for casual viewers. Blake was disappointed with this decision, and had already ordered a specially-made birthday cake.

The second studio block for The Stones Of Blood spanned July 16th to 18th. The first two days were principally concerned with all of the material on the Megara spacecraft. To establish the vessel as a prison ship, it was decided to feature old Doctor Who monsters amongst the deceased convicts. In the event, only a Wirrn (from 1975's The Ark In Space) was seen, although permission had been obtained to feature a Sea Devil (from 1972's The Sea Devils). Also taped on the 16th was the White Guardian's warning. This was read by Gerald Cross -- one of the Megara voice artistes -- in order to avoid having to rehire Cyril Luckham, who had portrayed the Guardian in The Ribos Operation at the start of the season. July 17th, meanwhile, also saw the completion of the material in Vivien's cottage, as well as various effects shots.

This left the sequences set within the TARDIS to be taped on July 18th, in addition to some remaining effects work. Although the planned birthday segment had been abandoned, the cake Blake had ordered arrived anyway, and it was enjoyed by the cast and crew to celebrate the serial's completion. In post-production, Blake decided to alter the cliffhanger ending to Episode Two. Originally, this was the Ogri attack on the Doctor and Professor Rumford as they explored the cellar of De Vries' house. That material was instead pushed back to Episode Three, and Romana's abduction into hyperspace was brought forward in its place.

Since the start of Season Sixteen, the quiz show Noel Edmonds' Lucky Numbers had been Doctor Who's lead-in, but its run had ended the week before The Stones Of Blood premiered. On October 28th, Episode One was instead delayed by five minutes to accommodate the broadcast of Grease Day USA, a spotlight on the popular movie musical Grease starring John Travolta and Olivia Newton-John. The following week, The Basil Brush Show returned to the BBC Saturday evening schedules in the timeslot immediately preceding Doctor Who.

• Doctor Who Magazine Summer Special 1995, “Archive: The Stones Of Blood” by Andrew Pixley, Marvel Comics UK Ltd.
• Doctor Who Magazine Special Edition #9, 22nd December 2004, “I'll Put You Together Again” by Andrew Pixley, Panini Publishing Ltd.
• Doctor Who: The Complete History #29, 2017, “Story 100: The Stones Of Blood”, edited by John Ainsworth, Hachette Partworks Ltd.
• Doctor Who: The Handbook: The Fourth Doctor by David J Howe, Mark Stammers and Stephen James Walker (1992), Virgin Publishing.
• Doctor Who: The Seventies by David J Howe, Mark Stammers and Stephen James Walker (1994), Virgin Publishing.
• In·Vision #34, October 1991, “Production” edited by Justin Richards and Peter Anghelides, Cybermark Services.