Should I write about extracurricular activities on my personal statement?

Extracurricular activities directly related to your subject e.g. a summer project, a CREST award or work experience, are a great thing to talk about in an Oxbridge personal statement! However, it is unnecessary to talk at length about non-academic extracurriculars- Oxbridge are looking for students with a passion for their subject, regardless of whether they are well-rounded or not! Nevertheless, if a significant amount of your time is devoted to excelling at a particular hobby, it is worth mentioning in brief to show good time management.