Valiant (aircraft carrier)
The Valiant was a large flying aircraft carrier used by UNIT some time in the early 21st Century. It contained various rooms including a conference room and many engine corridors. It was kept secret from public knowledge but politicians such as the President Winters of the USA and the Master as Harold Saxon, Prime Minister of Great Britain knew of it.
Every detail of it was designed by Mr. Saxon, and it was used for the first Human contact with the "Toclafane". (DW: The Sound of Drums)
In the following year in an erased timeline, the Valiant seems to have formed the Headquarters of the Master, Himself rarely comming down. Both the Jones family (with exeption of Martha) and Captain Jack Harkness were imprisoned on the ship, as was the doctor. It also held the Paradox Machine. When this timeline was erased, the Valiant was the only point in space and time not to revert. (DW: Last of the Time Lords)
Presumably UNIT regained controll of the ship afterwards
