We have had people on this forum making  enquiries about the use of “Medical Cannabis” in the workplace. I have recently viewed  this guidance from the government which largely follows the advice that  been generated by forum users but consolidates it into one website.

In summary it says:

• It is possible to obtain “medical cannabis” but only on prescription and those prescriptions are only available for a limited number of conditions
• Even if you have  “medical cannabis” you need to keep a copy of your prescription with you along with ID to prove that you are entitled to carry it, otherwise you  can be arrested for possession
• The “medical cannabis” does not come in the form of actual plant material or resin. It comes as a tablet or pill.
• CBD products are not the same as they do not( or should not)  contain THC, the substance in cannabis plants that makes you high. They are treated  legally as herbal supplements  not medicines
• Some (most?)  CBD products which you can by on-line contain at least some THC and as such are illegal to possess.