Christian,
i'm not sure if its the paper you've got wind of, but i (many years ago..) saw a memo from a junior defence minister, apparently on prompting from a cabinet minister from outside MOD, asking if a runway could be built at either South Georgia or Tristan de Cunha.
it was long the lines of 'i know this is a stupid question, but X from Z dept has looked at a map of the South Atlantic and asks if...' with the reply being 'the topography, as you suspected, makes it impossible/spectacularly difficult, as does the timeframe..'