Here are the 4 most common harassment offences and maximum sentences:
Harassment (section 2): a summary only offence, carrying a maximum of six months' imprisonment and/or a level 5 fine.
Stalking (section 2A): a summary only offence, carrying a maximum of six months' imprisonment and /or a level 5 fine.
Harassment involving Fear of violence (section 4): an either way offence, carrying a maximum of five years' imprisonment and/or a fine on indictment.
Stalking - involving fear of violence or serious alarm or distress (section 4A): an either way offence, carrying a maximum of five years' imprisonment and/or a fine on indictment.
(Summary only offences = Dealt with by Magistrates Court, Either way offences = Mags or Crown Court).