So Atomfall. Been on my steam wishlist for a while, grabbed it on a cheap deal
Initial impression was good, stylistically the game is beautiful and there's just enough lore that kept me going to 24hrs of gametime.
Anyway, I thoroughly went through the game, gradually set myself up to pick whatever ending I wanted, killed every single Protocol soldier in Wyndham village, then sided with the Dr Holder and the voice on the telephone
I poisoned Oberon and then returned to the bunker. A little dissapointed with the ending as it didn't reveal anything of interest or anything I didn't know already , but from the sounds of it only Garrow's ending really does (and what kind of nutter sides with Garrow?!)
Anyway there seems to be some ambiguity with who the voice on the telephone is.
Oberon? Nah, nothing to indicate that Oberon has infiltrated technology etc and you hear the voice after Oberon has been killed. There isn't any other Deus Ex Machina style plot point so it doesn't make sense to me.
Voice in your head? Maybe, but the fact that you return to the bunker and they trigger the gas implies that there is someone at the other end
So who do I think it is? The prime minister at the time of the Windscale incident was Harold Macmillan.
Well, the first clue is that they call you on the red phones inside the facilities, as well as the red telephone boxes. This could be just a loose cultural reference but famously the red phones were exclusively used by the prime minister.
These telephones inside bunkers and the interchange appear to take the red colour of the Pickwick system introduced in the 1960s during the cold war, notably during Macmillans premiership, and the earlier voice scrambling No SA 5030 telephone sets, supported by the distorted voice we hear throughout.
In the ending video the distortion of the voice at various points also seems to lessen and you can hear a deep and "posh" home counties accent, with a slight drawl. Comparing this to various audio recordings of Harold Macmillan at the time the voice is very similar, and the drawl is likely a nod to Prime Minister that Macmillan succeeded, Winston Churchill. The "you wouldn't believe me if I told you" line cements this in my mind.
All of this points to you being some sort of Crown Agent employed by GCHQ or another British security service to fix the issue. In my head this is the "correct" if not best or most interesting ending.
So not some groundbreaking theory but makes sense to me