Which of course, was one of the first things to go out the window when the John Nathan-Turner era ended. I even think the one Sylvester McCoy used in the McGann movie was the exact same model last seen in the series.I don't know if it was destroyed to stop it from being silly, but it was never used again during the original run of the program.
The writer of The Vistation destroyed it because he needed to keep the Doctor locked up for another half episode - he'd assumed that the Doctor had spares in the TARDIS, so it wouldn't be permanent.
The producer of the time thought that the screwdriver made things too easy for the Doctor, and decided that the scripted scene was the end for THE sonic screwdriver, not A sonic screwdriver.
Sonic Screwdriver from the McGann Movie
