Thames House

Thames House was the headquarters of MI5, located in London.

When the 456 returned to Earth, a special tank was built to house their ambassador on the thirteenth floor. (TW: Children of Earth: Day Two)

Jack Harkness and Ianto Jones confronted the 456 ambassador at Thames House. The 456 released a virus which killed everyone the building, except Dekker who survived by wearing a hazard suit. (TW: Children of Earth: Day Four)