FrankW has been selective in her quote.
Here's the full version of the CPS website description of stalking:
"There is no legal definition of 'stalking'. Neither is there specific legislation to address this behaviour. Rather, it is a term used to describe a particular kind of harassment. Generally, it is used to describe a long-term pattern of persistent and repeated contact with, or attempts to contact, a particular victim.
"Examples of the types of conduct often associated with stalking include: direct communication; physical following; indirect contact through friends, work colleagues, family or technology; or, other intrusions into the victim's privacy. The behaviour curtails a victim's freedom, leaving them feeling that they constantly have to be careful.
"In many cases, the conduct might appear innocent (if it were to be taken in isolation), but when carried out repeatedly so as to amount to a course of conduct, it may then cause significant alarm, harassment or distress to the victim."