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

ü

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

ü

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

FMR LLC

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

See Section 9

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

27 January 2016

6. Date on which issuer notified:

28 January 2016

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

10%

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

Indirect

Direct xi

Indirect xii

Direct

Indirect

GB0030544687

25,268,988

25,268,988

25,318,788

25,318,788

9.64%

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

Right of Recall

790,800

0.30%

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

Nominal

Delta

Total (A+B+C)

Number of voting rights

Percentage of voting rights

26,109,588

9.94%

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

Proxy Voting:

10. Name of the proxy holder:

11. Number of voting rights proxy holder will acquire:

12. Date on which proxy holder will acquire voting rights:

13. Additional information:

None

14. Contact name:

Sally-Ann Hatton

15. Contact telephone number:

[email protected], 01737 837148