Threshold

The Threshold were an organisation created by the "partnership" of Abraham White and the Pariah, a living weapon of great power created on Gallifrey.

History
The Threshold began their careers as profiteers and used their transport window capabilities to carry out important missions from their clients.

The Threshold eventually came under a contract to the Lobri, a race of spider-like parasitic entities who were trapped on a plane of reality that held together the link between human minds. The Threshold supplied the Lobri with the resources required to instigate a breakout, a large gathering of humans at the Notting Hill Carnival, and later supplied them with three of the Doctor's previous companions, Peri, Ace and Sarah Jane Smith. This allowed them to gain enough power to escape the dimension. (DWM: Ground Zero)