Holding(s) in Company

TR-1: NOTIFICATION OF MAJOR INTEREST IN SHARESi

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

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

x

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

x

An event changing the breakdown of voting rights

Other (please specify):

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

The Goldman Sachs Group, Inc.

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

Goldman Sachs International

Goldman, Sachs & Co.

Goldman Sachs Asset Management, L.P.

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

17 October 2016

6. Date on which issuer notified:

19 October 2016

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

Above 3%

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

GB0030544687

Below 3%

Below 3%

173,049

0.06%

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

Stock Loan (Physical)

Open

3,499,643

1.16%

Total (A+B+C)

Number of voting rights

Percentage of voting rights

9,079,916

3.01%

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

-----------------The Goldman Sachs Group, Inc.; 9,079,916 shares; 3.01%

Goldman Sachs (UK) L.L.C. (Controlled by The Goldman Sachs Group, Inc.)

Goldman Sachs Group UK Limited (Controlled by Goldman Sachs (UK) L.L.C.)

Goldman Sachs International (Controlled by Goldman Sachs Group UK Limited)

The Goldman, Sachs & Co. L.L.C. (Controlled by The Goldman Sachs Group, Inc.)

Goldman, Sachs & Co. (Controlled by The Goldman, Sachs & Co. L.L.C.)

GSAM Holdings LLC (Controlled by The Goldman Sachs Group, Inc.)

Goldman Sachs Asset Management, L.P. (Controlled by GSAM Holdings 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:

Please note, total amount of voting rights have been rounded to 2 decimal places therefore there is a possibility of a rounding error.

General email contact:

[email protected]

14. Contact name:

Joanna Foley

15. Contact telephone number:

+44 207 051 9996