Holding(s) in Company

TR-1: Notifications of Major Interests in Shares

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

Opsec Security Group Plc

2. Reason for notification (yes/no)

An acquisition or disposal of voting rights

X

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

An event changing the breakdown of voting rights

Other (please specify):______________

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

Herald Investment Management Limited

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

Bank of New York (OCS) Nominees Ltd on behalf of Herald Investment Trust Plc

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

22 August 2008

6. Date on which issuer notified:

27 August 2008

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

12.93%

8: Notified Details

A: Voting rights attached to shares

Class/type of shares

If possible use 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

Percentage of voting rights

Direct

Indirect

Direct

Indirect

GB0000462191

6,118,924

6,118,924

6,903,924

(12.93%)

6,903,924

12.93%

B: Financial Instruments

Resulting situation after the triggering transaction

Type of financial instrument

Expiration date

Exercise/ conversion period/date 

No. of voting rights that may be acquired (if the instrument exercised/converted)

Percentage of voting rights

None

Nil

Total (A+B)

Number of voting rights

Percentage of voting rights

6,903, 924

12.93%

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

Herald Investment Management Limited, a discretionary investment manager, is the parent undertaking of an investment management business.

Shareholder: Herald Investment Trust (in the name of Bank of New York (OCS Nominees Limited

6,903,924 shares - 12.93%

Total for Funds under the management of Herald Investment Management Limited

6,903,924 shares - 12.93%

Proxy Voting:

10. Name of 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:

Andrew Miller

15. Contact telephone name:

020 7553 6308