This is the Butler's T.A.R.D.I.S. It's a type 89 T.A.R.D.I.S meaning it is the most advanced non military T.A.R.D.I.S. When he heard about the Time War, he immediately left Gallifrey and simply said that he will return in a century or two. The Butler is a Geneticist.
Click on the sprite. It is based off of the type fourty default tardis.
