Cannabis is classified as a Class B drug in the UK, making recreational use illegal with penalties up to five years in prison.

Under UK law, cannabis possession remains illegal for adults outside of prescribed medical use. The Misuse of Drugs Act 1971 places cannabis in Class B, reflecting a stance that it carries significant risks but is not the most dangerous substance. Possession can lead to fines or prison sentences of up to five years, while supply or trafficking carries harsher penalties, including up to 14 years imprisonment. Despite this strict classification, enforcement has seen some local variations, with police sometimes opting for warnings or diversion schemes rather than prosecution.