The GW Group was founded in early 1998 by Dr. Geoffrey Guy. Shortly thereafter, Dr. Guy was joined by Dr. Brian Whittle, thereby reuniting the team that previously founded the company which became Phytopharm, the plant medicines company, which floated on the Official List of the London Stock Exchange in April 1996. GW was first granted licenses by the Home Office in June 1998 to cultivate, produce, possess and supply cannabis for medical research purposes. Since its inception, GW has worked closely with officials from the Home Office.