Teleport control

From Tardis Wiki, the free Doctor Who reference

A teleport control was a device added to the Second Doctor's TARDIS with a Stattenheim remote control stored inside its perspex dome shape. It gave the Time Lords "dual control" over the TARDIS. When pointing out the new addition to Jamie, the Doctor shouted "You'd think I'd never flown a TARDIS solo before!" He promised Jamie that he would complain when their mission to talk to Dastari was over. He took the recall disk from inside it. (TV: The Two Doctors)

According to one account, the control and the interior changes were created by linking the Stattenheim remote of a CIA member with the TARDIS and synchronising it with Gallifrey. After the mission with Dastari and the Sontarans, the Doctor smashed the dual control mechanism and shut off the temporal synchronisation. (AUDIO: The Black Hole) According to another, the control and the remote were installed after the Celestial Intervention Agency gave the TARDIS a "complete overhaul" as a reward for the Doctor's good performance on their mission to defeat the Players in Napoleonic France. It was an addition the Doctor very much protested. (PROSE: World Game)