Object
Chameleon Tours Blank Postcards
; discovered by the Doctor in the abandoned Chameleon Tours cubicle in Part 1, stacked with unused foreign stamps as clues to Polly's disappearance
2 appearances
Purpose
Deceive authorities and families into believing missing people like Polly and Brian Briggs are safely traveling overseas
Significance
Key clue exposing the Chameleon Tours alien conspiracy; Gascoigne's discovery of them led to his murder, and the Doctor's find in the cubicle confirms the operation's scope, spurring his pursuit as Ben's abduction unfolds on the monitor
Appearances in the Narrative
When this object appears and how it's used