"The cannabis plant has 70 different cannabinoids in it, and each has a different effect on the body," said Justin Gover, managing director of GW Pharmaceuticals.

"Some can stimulate your appetite, and some in the same plant can suppress your appetite. It is amazing both scientifically and commercially."

GW is known for developing Sativex, a medicine derived from cannabis prescribed to multiple sclerosis patients. Sativex, a sub-lingual spray, has been approved for use in Canada, but has yet to be permitted in GW's home country of Britain.

The cannabis plants used to produce these medicines are grown indoors in a secret location in Southern England under high security.

GW plans to begin clinical trials of the new drug in the second half of this year.