Greyhound Two
From Tardis Wiki, the free Doctor Who reference
Greyhound Two was a UNIT call sign which was used by both Brigadier Alistair Gordon Lethbridge-Stewart (TV: The Dæmons) and Captain Mike Yates. (TV: Day of the Daleks) It was later used by Colonel Vikram Shindi (AUDIO: House of Silents) and Osgood, Kate Stewart's scientific advisor. (AUDIO: Call to Arms)
