Margaret Blaine

Margaret Blaine was a member of MI5. In 2006, however, Blon Fel-Fotch Passameer-Day Slitheen killed her in order to use her as a skinsuit as a diguise. (DW: Aliens of London/World War Three)). Still posing as Margaret Blaine, Blon Fel-Fotch Passameer-Day Slitheen later got elected Lord Mayor of Cardiff. The Doctor defeated "Blaine"'s scheme and returned the Slitheen to her home world. The empty skin is left on the TARDIS floor; it is not known what happened to it afterwards. (DW: Boom Town)

A clipping announcing "Blaine's" election as mayor still adorned the information booth/main entrance to the Torchwood 3 hub several years later (TW: Reset).