Osterhagen Key

The Osterhagen Key was a device possessed by UNIT that triggered the Osterhagen Project, a set of nuclear warheads that would initially go off. Martha Jones was handed the key in 2009 by General Sanchez, during the Dalek Invasion of Earth. (TV: The Stolen Earth)

Usages
The Osterhagen Project was once activated in 2009, and Martha Jones was handed the Key to the Osterhagen Station in Germany. She established contact with Osterhagen Station 4 and 5, and decided to activate it. In the midst, she contacted the Dalek Crucible and threatened Davros that she would activate the project., since Davros needed all 27 planets, and with one gone, his master plan would fail. Davros, not wanting to let go of Earth nor his plan, teleported Martha to the Crucible, and the project failed. (TV: Journey's End)