The Making of The Trial of a Time Lord: Part One - Mysterious Planet

 was the first of four documentaries in the Making of The Trial of a Time Lord series. As the name suggested, it concerned itself with the making of The Mysterious Planet. It was by far the longest of the four parts. It was the only one of the four documentaries which did not bear the full name of the serial under discussion.

Topics discussed
The documentary opened with a clip of Colin Baker on Blue Peter contemporaneous with the start of season 23. Eric Saward then explained that the basic conceit of the trial came from Jane Judge, his partner and the production secretary on Doctor Who at that time. Jim Sangster, Baker, and Saward then opined on the relative merits of the trial scenario.

The interviewees then talked about the merits of having a Robert Holmes script for the first segment of The Trial. Sangster and Saward spent time discussing the savage notes the Head of Drama, Jonathan Powell, gave on Holmes' scripts — and how the production team largely ignored those notes.

Nicola Bryant and Dominic Glynn then talked about the effect and composition of the new season 23 theme music.

Mike Kelt and Clayton Hickman then examined the creation of the model shot used to open episode one. Glynn remarked how the script's description of the space station as a "cathedral" inspired him to use instruments common to churches, like bells and organs. Kelt then went into great detail on how motion control was used to achieve the effect. Colin Baker then considered whether it was wise to spend so much of the serial's — and, indeed, season's — budget on that one shot.

Saward then began an examination of the trial segments themselves. Baker and Michael Jayston then opined that some of the trial segments could have been improved if the Sixth Doctor's penchant for punning on the Valeyard's name had been excised. Both felt that the characters should've been allowed to meet each others as equal wits in the trial room, rather than the Doctor being so, as the Inquisitor put it, "puerile".

Bryant, Baker, Saward and Hickman next talked about how the relationship between the Sixth Doctor and Peri was different in this story than it had been in series 22.

Tony Selby then related how he first met John Nathan-Turner and how that meeting directly led to him being cast as Sabalom Glitz. Following that, Baker, Bryant and Sangster reflected on the "stunt" casting of Joan Sims.

There then followed a discussion of how OB video allowed for greater rehearsal time for location filming.

Kelt then returned to explain the construction and use of the L1 robot, which was unusual as robotic props went, because it had to work even on rough, forested terrain. A clip from Blue Peter followed in which the robot's designer, Mike Ellis, had a chat with his daughter, Janet Ellis, a presenter on that program. The L3 robot was also discussed as being perhaps more technically problematic than the L1.

The documentary ended with a touch of remorse on the part of Eric Saward that perhaps the production let the script down slightly, and a note from Bryant and Sangster of how the ending of Planet foreshadowed Peri's demise.