Regulation 5
Where any controlled drug (other than a drug specified in Schedule 1 to these Regulations) is kept otherwise than in a locked safe, cabinet or room which is so constructed and maintained as to prevent unauthorised access to the drug, any person to whom this Regulation applies having possession of the drug shall ensure that, so far as circumstances permit, it is kept in a locked receptacle which can be opened only by him or by a person authorised by him.
Paragraph (1) of this Regulation applies to any person other than—
a person to whom the drug has been supplied by or on the prescription of a practitioner for his own treatment or that of another person or an animal; or
a person engaged in the business of a carrier when acting in the course of that business; or
a person engaged in the business of the Post Office when acting in the course of that business.