Harry (An Adventure in Space and Time)

Harry was a security guard at the British Broadcasting Corporation television centre in the 1960s on Earth.

He was in his old age and wore a well kept uniform. He would often talk to people that entered the centre. (DOCUDRAMA: An Adventure in Space and Time)

Behind the scenes
It is unknown if Harry existed in the real world, as the character was added so William Russell could appear as an Easter egg, due to his contribution to the early years of Doctor Who by playing Ian Chesterton.