Prescribed use has been legal in the UK since 2018 but many police officers appear to be uninformed. On a pleasant August evening on the seafront in Plymouth, Sal Aziz, a 24-year-old NHS administrator, was relaxing with his sister and discussing what to do for her birthday. Aziz, who is legally prescribed medical cannabis for anxiety and depression, inhaled some of his medicine from a vaporiser. About 10 minutes later, two police officers arrived and…