For games masters seeking inspiration directly from the source material what better place to start? Who was this police officer and how can he impact upon your own adventures and campaign?
Just A Police Officer
The most mundane answer is that he is just a normal police officer. That doesn’t mean that his life is ordinary or that the PCs might not meet him in a different adventure.
If Totter’s Lane is part of his patrol he might have been part of the investigation resulting from the disappearance of two school teachers and their pupil. The PCs might encounter him as they try to prevent the authorities from looking too closely into this event.
The police officer could feel guilty about not noticing something was amiss. While others are willing to close the case he might continue to search for clues years later. He might even begin to put the pieces of the puzzle together and guess at the Doctor and Susan’s unearthly origins.
Based in London and with the UNIT era fast approaching the same police officer could become involved in the events of ‘Remembrance of the Daleks’, ‘The War Machine’, ‘Web of Fear’, ‘The Invasion’ and any of the UNIT stories.
PCs could meet him if their adventure runs in parallel to these events. This would make him stand out from the other NPCs, even if it is just a minor background detail. If they meet him after the events it is just another way that this minor character is entwined in Doctor Who mythology.
It could be a nice way to tie back to this starting point if the police officer becomes a companion, especially if the Doctor is a PC. This can act as reward for his diligence and act as a reminder for the Doctor that his actions have consequences.
The Last Doctor
I didn’t write ‘the 13th Doctor’ because there is no guarantee that the Doctor won’t get more incarnations. Regardless it makes sense for the the Doctor, at the end of his long life, to come back to this pivotal moment.
This was when Ian and Barbara taught him to be a hero, rather than just a tourist. He might also have wanted to see Susan just one more time. Certainly he wouldn’t want to change anything (or would he?)
This would also bring the story of Doctor Who full circle. Whether it is truly the end is up to you.
The PCs could either be the Last Doctor (maybe finding a way to go on) or outsiders who happen to learn the true identity of the police officer. They could be there simply at witnesses or an adventure could spring out of this (maybe his enemies have followed him to this moment). It could act either as a beginning of a campaign (the passing of a torch) or the end.
The police officer might not be human at all and could be searching for the Doctor or the TARDIS. They might either know of them or have technology which has traced them to this area of London. The police officer is a perfect disguise as they blend in yet also possess authority.
The alien agent could be in London specifically to hunt the Doctor (in which case the PCs must stop them to avoid history being altered) or just coincidentally carrying out their own scheme (in which case the PCs can try to stop them in an adventure that is happening parallel to ‘The Unearthly Child’.)
Linked to the idea above this could be a Time Lord hunting the Doctor and Susan. We know from ‘The War Games’ that once they knew where he was they captured the Doctor and they might very well be searching for him (or the Hand of Omega).
It is likely that the Doctor and Susan have been in 1960s London for a few months at least. This could be how the Time Lords were able to track them. If the Doctor was aware of they were getting close (maybe he saw the police officer near the yard) this could have influenced his decision to leave in such a hurry.
This could be the background detail of a Time Lord PC. This could be there connection to the Doctor (tenuous as it is). They might also have been there to ensure that this moment in history wasn’t affected (maybe crossing time streams in order to do so).
Knowingly or unknowingly this police officer might have threatened the Doctor’s history. It could be that he was closing in on the Doctor (likely for stealing parts for the TARDIS) and might have arrested him.
This could have delayed or entirely prevented him from leaving in the TARDIS. If he was arrested before Ian and Barbara’s investigation of the yard he wouldn’t be there to influence events. They could have found Susan and taken her into care before he could free himself. He’d either have to travel on alone or spend more time in 1960s London getting her back.
The Doctor’s time travelling enemies might work out that this is a vital point in his timeline and attack it. ‘The Name Of The Doctor’ shows how changing the Doctor’s past could have disastrous consequences for the universe.
The PCs can be on hand to prevent these alterations from history. Either they learn about the attempt to change history and travel back or they unknowingly ensure that things proceed as they should, as they are already part of the predestined timeline.
After we see the policeman we are then shown the TARDIS in the scrapyard. We don’t know how much time passes from the first scene to the next so this could be when the TARDIS arrived.
If it was designed to blend in with its surroundings why does it resemble a police box. Ian’s reaction indicates that these are usually found on the street. It is possible that it did arrive on a street and the Doctor and Susan then moved it (either physically or via a sort hop).
It could be that the TARDIS based its form on the expectations of the nearest living being when it arrived in the scrapyard, which just happened to be a police man. Maybe at the time he was thinking about returning to the shelter of a nearby police box, which influenced the TARDIS.
This would mean that the police officer was unknowingly responsible for an iconic part of Doctor Who. If there was something unusual about the police officer that might also explain why the chameleon circuit breaks, keeping it in that form.
The Doctor (or a PC who finds this out) might later try to track the police officer down to find out how this happened. It could be that the police officer has a very powerful mind that others might exploit. He might also be key to fixing the TARDIS.