Holding(s) in Company

1. Identity of the issuer or the underlying issuerof existing shares to which voting rights areattached: ii

GW PHARMACEUTICALS PLC

2 Reason for the notification (please tick the appropriate box or boxes):

An acquisition or disposal of voting rights

X

An acquisition or disposal of qualifying financial instruments which may result in the acquisition of shares already issued to which voting rights are attached

An acquisition or disposal of instruments with similar economic effect to qualifying financial instruments

An event changing the breakdown of voting rights

Other (please specify):

3. Full name of person(s) subject to thenotification obligation: iii

The Bank of New York Mellon Corporation

4. Full name of shareholder(s)  (if different from 3.):iv

The Bank of New York Mellon; The Dreyfus Corporation; The Boston Company Asset Management LLC; BNY Mellon, National Association; Pershing LLC; BNY Mellon Capital Markets, LLC

5. Date of the transaction and date onwhich the threshold is crossed orreached: v

27 June 2016

6. Date on which issuer notified:

28 June 2016

7. Threshold(s) that is/are crossed orreached: vi, vii

Falling below 5%

8. Notified details:

A: Voting rights attached to shares viii, ix

Class/type ofshares

if possible usingthe ISIN CODE

Situation previousto the triggeringtransaction

Resulting situation after the triggering transaction

NumberofShares

NumberofVotingRights

Numberof shares

Number of votingrights

% of voting rights x

Direct

Direct xi

Indirect xii

Direct

Indirect

Common Stock GB0030544687

ADR

12,149

1,095,460

12,149

13,145,517

12,149

913,068

N/A

N/A

12,149

10,956,813

N/A

N/A

0.0046%

4.1671%

US36197T1034

B: Qualifying Financial Instruments

Resulting situation after the triggering transaction

Type of financialinstrument

Expirationdate xiii

Exercise/Conversion Period xiv

Number of votingrights that may beacquired if theinstrument isexercised/ converted.

% of votingrights

N/A

C: Financial Instruments with similar economic effect to Qualifying Financial Instruments xv, xvi

Resulting situation after the triggering transaction

Type of financialinstrument

Exercise price

Expiration date xvii

Exercise/Conversion period xviii

Number of voting rights instrument refers to

% of voting rights xix, xx

N/A

Nominal

Delta

Total (A+B+C)

Number of voting rights

Percentage of voting rights

10,968,962

4.17%

9. Chain of controlled undertakings through which the voting rights and/or thefinancial instruments are effectively held, if applicable: xxi

The Bank of New York Mellon Corporation is making this disclosure as the ultimate parent company of: The Bank of New York Mellon; The Dreyfus Corporation; The Boston Company Asset Management LLC; BNY Mellon, National Association, Pershing LLC, and BNY Mellon Capital Markets, LLC

Proxy Voting:

10. Name of the proxy holder:

N/A

11. Number of voting rights proxy holder will ceaseto hold:

N/A

12. Date on which proxy holder will cease to holdvoting rights:

N/A

13. Additional information:

N/A

14. Contact name:

Andrew Weiser

15. Contact telephone number:

516-338-3752