As the Doctor and Sarah Jane Smith drive through an abandoned London in Bessie, seeking to thwart the Dahensa invasion, Sarah points out the Post Office Tower as the tallest building in the city. Though having some bad experiences with the building, the Doctor concedes the point and drives off.
Briefly, the Doctor remembers his Sarah Jane and the great woman she became.
When the two arrive at the Post Office Tower, the Doctor sets up a sonic manifold feedback loop across London as Sarah fends off a Dahensa. The sound disorients the aliens and they quickly withdraw from Earth.
Finishing the memory, the Doctor remarks that protecting the Earth is essentially his job. And not just the UK, but the whole planet. A planet whose every city he's been to. Especially the one that was named twice.
- The Doctor and Sarah drive Bessie through the streets of evacuated London. They drive past the statue of Winston Churchill opposite the Houses of Parliament.
- The Post Office Tower is the tallest building in London.
- The Doctor drives past the Fitzroy Tavern, a significant real world meeting place of Doctor Who fans.
- The Doctor mentions that he was warned of the Dahensa invasion by Grigori Rasputin. (AUDIO: The Wanderer)
- The Twelfth Doctor calls his third incarnation "Fancy Pants". (TV: The Five Doctors)
- The Doctor is apprehensive about going to the Post Office Tower, citing a bad experience "with a mad computer". (TV: The War Machines)
- New York City is mentioned as having been named twice. (TV: Daleks in Manhattan)