TV One of the more eccentric elements of early Who includes the lengths the production team had to go through in order to produce each week’s episode, particularly in unforeseen circumstances.
During the making of The Keys of Marinus it was agreed that each of the regulars would have a couple of weeks off and in that and each ensuing story, other characters were brought in, sections were pre-filmed and scripts extensively rewritten to accommodate this much needed holiday.
With the show being made in series of over forty episodes, who could blame them? Did the public, as they would now, notice that the participation of the regulars were extensively scaled back in those weeks? Was there talk of a Susan-lite episode?
But sometimes, such changes were so last minute that they utterly changed the fabric of what was on screen, or as in the case of The Mind Robber enhanced it.
When Frazer Hines contracted chicken pox, there wasn’t much that could be practically or convincingly done to write the character out. So they recast.
A scene was written in which the Doctor and Zoe were forced to put the features of a cut-out version of Jamie back together to save him.
They fail and in walks Hamish Wilson playing Jamie for the rest of the episode and quite well too, blending seemlessly into the mayhem of the Land of Fiction.
By the next episode, Frazer was back, Jamie’s face put back to normal.
But our understanding of the environment became richer. Darker. It doesn’t just have the capacity to create fictional characters from the minds of the Doctor his companions, it can materially change them too.