Medical cannabis has been legal in the UK since 2018, but is strictly regulated...

https://soulinner.com/can-medical-cannabis-actually-help-uk-insomnia-sufferers/

Medical cannabis has been legal in the UK since 2018, but is strictly regulated by specialists. Typically considered only after other sleep treatments fail, it isn't a first-line option. Experiences vary, so consult a doctor about your needs.