Safety and security issues are very important, not just as you first arrive in the UK, but also throughout your stay. By international standards the UK is a safe country. In a recent survey by the British Council only a very small proportion of students had ever experienced a crime and the overwhelming majority felt that the UK is a very safe place to be.
However, it is important to be aware of how you can keep you and your possessions safe and the British Council's online guide is an excellent resource.
Personal safety: British Council
Frauds and Scams: UKCISA