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:

ARK THERAPEUTICS GROUP 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 the notification obligation:

Smith & Williamson Holdings Limited

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

See section 9

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

22.07.10

6. Date on which issuer notified:

27.07.10

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

GB0034251727

 10,029,600

10,029,600

11,029,600

5.28%

B: 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

 N/A

Nominal

Delta

Total (A+B)

Number of voting rights

Percentage of voting rights

 11,029,600

5.28%

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

Smith and Williamson Nominees Limited, a subsidiary of Smith and Williamson Investment Management Limited, a subsidiary of Smith and Williamson Holdings Limited - 3,759,600 shares

Bank of New York Nominees as custodian for Smith & Williamson Investment Management Limited, a subsidiary of Smith & Williamson Holdings Limited - 1,150,000 shares

BNP Paribas as custodian for Smith and Williamson Investment Management Limited, a subsidiary of Smith and Williamson Holdings Limited - 320,000 shares

BNP Paribas Securities Services as custodian for Smith & Williamson Investment Management (Ireland) Limited, a subsidiary of Smith & Williamson Holdings Limited - 5,625,000

Proxy Voting:

10. Name of the proxy holder:

 N/A

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

 N/A

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

 N/A

13. Additional information:

14. Contact name:

Stephen Hamilton-Jones, Smith & Williamson Investment Management Limited

15. Contact telephone number:

020 7131 4734