Posting of Shareholder Circular

GW Pharmaceuticals PLC

Shareholder Circular and Notice of General Meeting

Porton Down, UK, 22 March 2013: GW Pharmaceuticals PLC(AIM: GWP, "GW" or the "Company") hereby provides notification that, following the announcement on 19 March 2013 that it had filed a registration statement with the U.S. Securities and Exchange Commission for an initial public offering of American Depositary Shares on the NASDAQ Global Market, an explanatory document has today been sent to all GW shareholders. The document incorporates a letter from the Chairman and a Notice of Meeting convening a General Meeting to be held at 9.30 a.m. on 12th April 2013, in order for shareholders to vote upon the resolutions required to proceed with the offering.

The document is now available on the Company website at www.gwpharm.com.

Amongst the resolutions to be considered at the General Meeting is a resolution to approve proposed amendments to the Company's Articles of Association. A draft of the proposed amended Articles of Association is also available on the Company website.

For further information, please contact:

GW Pharmaceuticals PLC Tel: +44 (0)1980 557 000

Adam George, Company Secretary

Peel Hunt LLP (Nominated Adviser) Tel: +44 (0)207 418 8900

James Steel/Vijay Barathan