Professor Padraic Ratigan was the arch-nemesis of Basil of Baker Street and the world's greatest criminal mind. Ratigan was an evil and self-hating rat who posed as "a big mouse" (the reasons for his self-loathing remain unrevealed). He masterminded his grandest scheme, to replace the mouse queen with a mechanical double and take over the kingdom, and to this end he had Fidget kidnap Hiram Flaversham. Ratigan is thought to have been killed falling from Big Ben during a fight with Basil, after Basil foiled his plan.
Ratigan is an obvious counterpart to Professor Moriarty.