Guldreasi

The Guldreasi were a race who attempted to make Earth a slave planet for its war machine.

In the 22nd century, the Guldreasi contacted Susan Campbell to try to gain the human race's trust with a peace treaty. The negotations failed when the Guldreasi detected the Doctor's TARDIS in London, and thought it a trap.

The Eighth Doctor revealed the Guldreasi's plans to make humans a slave race and the Earth Council banished the Guldreasi from Earth. (AUDIO: An Earthly Child)