[mickmc]

I think if you read the MED 3 sick note carefully, it say " I advise that you refrain from work for a period of....."

Therfore it is advice not an instruction that you cannot work - in reality your Company should make a risk assesment both to you and your fellow employees of the possible risks in you coming back to work, if they deem them to be within acceptable limits there is no reason why you can't go back to work with a pot on

They may have to check with the Companies insurers though