The Doctor's whistle
From Tardis Wiki, the free Doctor Who reference
The Doctor's whistle was a tool found inside the Memory Tardis. Whose and What memory the Doctor's Whistle is from is unknown.
The Doctor's whistle appeared as a steel whistle on a red lanyard in the Empire of Death. The lanyard is the same color as the molecular rope. The Doctor's whistle has the ability to control the Tardis to an unknown extent.
Myths
The Doctor's Whistle is a sonic device. (Unconfirmed)
