Knew I had heard it somewhere...
Influencing HistoryEdit
The Seventh Doctor stated that interfering in Gallifrey's past time travel experiments was against the First Law. (PROSE: Cat's Cradle: Time's Crucible) Whether or not it was First, there was a Law traditionally preventing Gallifrey's 'present' from interacting with its own subjective past or future. (PROSE: Lungbarrow)