Brigadier Alistair Gordon Lethbridge-Steward is/was the commander of UNIT in the UK. He is also one of the Doctor's closest friends on Earth.
In part 3 of Mission to the Sun he fell of the top of the tower. Here he should have hit the ground. In the next part the Doctor traveled back in time and teleported the Brigadier away just before he hit the bottom. It is unknown where he got teleported to, but a trailer suggests Las Vegas.
50th Anniversary SpecialsEdit
The Brigadier made a cameo in the Third Doctor's special Escape of the Master .
He also appeared in a big part of The Caves of Han. It is unknown if this was before or after Mission to the Sun. He was voiced again by Harry (Junior_Creeper).
He also had his own mini special called 'The Terrible Brigadier'.
Series 2 Edit
The Brigadier returned as a companion during The Answer to Death, set three years after his last story.
The Valeyard Edit
The Brigadier was voiced by Matt (Didgeridoomen) in Prison of Monsters and by Harry Dunkley (Junior_Creeper) in Mission to the Sun and the 50th Anniversary specials. During series 2 and series 3, he was voiced by a third voice actor named Stephen Mansey (blueboxengine).