|Leader:||The Penumbra Chancellor|
|Type:||Time-Travel Opposition Group|
|Prominent Members:||Daevas, Serpentians, Tau Cetians, et al.|
|Affiliations:||The Pangalactic League|
|First Appearance:||Lily (mention)|
|Appearances:||Return to Earth|
|Size:||19 member species, 2 observer species|
The so-called Penumbra Cabinet had originally been formed as an intergalactic opposition group by various alien species capable of time travel as an alternative to the Infinity Knight High Command. In the aftermath of the Time Wave, it proclaimed itself to be the ultimate authority on trans-temporal matters and sought to impose its draconian Laws of Time across the Universe. Consequently, the Ninth and Tenth Inspectors had to operate outside its jurisdiction.
The Penumbra Cabinet inadvertently dissolved itself in the Tenth Inspector episode "Odyssey's Beginning". When the Blorgons suddenly reappeared in "Return to Earth", the penumbra ministers attempted to send a warning message back in time to the founders. Unfortunately, the received message altered the organisation's entire history, including the decision to send it, and therefore the message itself. The subsequent altered message changed the past in a different way, resulting in a cascade of variants, until an "equilibrium" history was reached in which the Penumbra Cabinet was never founded at all.