Jeffery

Tim Jeffery was a new science teacher at Park Vale School. Glune Fex Fize Sharlaveer-Slam Slitheen, disguised as headmaster Greg Blakeman, took Jeffery to the new science labs where Kist Magg Thek Lutiven-Day Slitheen tapped him on the shoulder. When Jeffery turned around, Kist Magg killed him and used his skin as a disguise.

Biography from the TARDIS Data Core article, licensed under CC-BY-SA