Oppressive British Culture as Embodied in Sir William Bradshaw
The kind of deep feelings Clarissa has and the madness Septimus experiences don’t fit in with British society. Sir William Bradshaw epitomizes (is the best example of) the British ideal and all of its sinister aspects – what Septimus calls "human nature." Bradshaw worships Proportion, which basically means that one must be reasonable and hide his or her emotions, emotions that serve as a criticism of society (which of course won't do). Since he majorly suppresses the individuality of our protagonists, we can certainly call Bradshaw the bad guy.