Holding(s) in Company

TR-1: NOTIFICATION OF MAJOR INTEREST IN SHARES

1. Identity of the issuer or the underlying issuer of existing shares to which voting rights are attached:

Rockhopper Exploration 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

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 the notification obligation:

GLG Partners LP

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

N/A

5. Date of the transaction and date on which the threshold is crossed or reached:

20/08/2010

6. Date on which issuer notified:

23/08/2010

7. Threshold(s) that is/are crossed or reached:

> 5%

8. Notified details:

A: Voting rights attached to shares

Class/type of shares

if possible using the ISIN CODE

Situation previous to the triggering transaction

Resulting situation after the triggering transaction

Number of Shares

Number of Voting Rights

Number of shares

Number of voting rights

% of voting rights

Direct

Direct

Indirect

Direct

Indirect

Ordinary shares

GB00B0FVQX23

1,424,342

1,424,342

1,424,342

1,424,342

0.74%

B: Qualifying Financial Instruments

Resulting situation after the triggering transaction

Type of financial instrument

Exercise price

Expiration date

Exercise/ Conversion Period

Number of voting rights instrument refers to

% of voting rights

CFD

N/A

N/A

N/A

8,265,631

Nominal

Delta

4.29%

4.29%

Total (A+B)

Number of voting rights

Percentage of voting rights

9,689,973

5.03%

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

GLG Partners is an investment management firm investing money on behalf of clients and investment funds.

Proxy Voting:

10. Name of the proxy holder:

Not applicable

11. Number of voting rights proxy holder will cease to hold:

Not applicable

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

Not applicable

13. Additional information:

Not applicable

14. Contact name:

Dan Johnson

15. Contact telephone number:

020 7016 7426