"The show was in a bad way in 1986. Ratings were plummeting, the effects were laughable and Colin's portrayal was lambasted left, right and centre. (Michael) Grade was dying to cancel it and he came within a whisper of doing so.
I was called to a meeting with him on the 5th floor. He told me that the next series would be the last. He asked me to oversee a storyline where the Doctor isn't killed off but left in some kind of time warp.
I said, 'Michael I can't and wont go down as the man who killed Doctor Who'
He asked me if I had something in mind. I said yes..."
John Nathan Turner 1999