10 Moments That Changed Doctor Who Forever

When Doctor Who returned in 2005, it quickly developed a habit of having an episode per series where the TARDIS team travel into Earth’s past and meet a well-known historical figure.

And usually, the Doctor does a pretty good job of making sure they don't cause any colossal changes to Earth’s timeline.

Usually.

In Tooth and Claw, the Tenth Doctor and Rose save Queen Victoria from a big bad werewolf, and in the process accidentally infuse some werewolf DNA into the British royal family. But since Queen Victoria isn't the type of person to just move past a terrifying encounter with a massive hairy alien, she orders the establishment of a secret organisation to track and combat extra-terrestrial threats: the Torchwood Institute.

This single action has so many massive and varied consequences that it would be impossible to list them all.

Torchwood's experimentation with the hole between universes in Army of Ghosts leads to the Battle of Canary Wharf and the arrival of the Dalek void ship, the first in a long line of dominoes that culminates in our old mate Dalek Caan breaking the Time Lock on the Time War, and Davros creating the Reality Bomb.

And that's without mentioning Rose being trapped in a parallel Earth and the many aliens defeated by Torchwood over the years, and it can all be traced back to the Doctor's accidental royal encounter in the Scottish countryside.