Holding(s) in Company

Synairgen plc
23 February 2007


TR-1:   NOTIFICATION OF MAJOR INTERESTS IN SHARES 

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

2. Reason for the notification     (please tick the appropriate box or boxes)

An acquisition or disposal of voting rights                                            (  )

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): Confirmation of our                                             X
holding___________________________________


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

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

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

6. Date on which issuer notified:                                 23 February 2007


7. Threshold(s) that is/are crossed or reached:                                     5%, 6%

8. Notified details:                                                                  -


A: Voting rights attached to shares
Class/type of     Situation previous to the  Resulting situation after the triggering transaction
shares            Triggering transaction

 if possible      Number of    Number of     Number of     Number of voting       % of voting rights
using the ISIN    Shares       Voting Rights shares        rights
CODE
                                             Direct        Direct    Indirect     Direct    Indirect

Ordinary 1p       1,314,211    1,314,211      1,314,211              1,314,211              6.05%
Shares
(GB00B0381Z20)


B: Financial Instruments
Resulting situation after the triggering transaction
Type of financial    Expiration date Exercise/ Conversion      Number of voting rights    % of voting
instrument                           Period/ Date              that may be acquired if    rights
                                                               the instrument is
                                                               exercised/ converted.
         -


Total (A+B)
Number of voting rights                            % of voting rights
1,314,211                                          6.05%


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

Chase Nominees - 743,836

Vidacos Nominees - 570,375

Proxy Voting:

10. Name of the proxy holder:

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

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

13. Additional information:

14. Contact name:                           John Ward

15. Contact telephone number:               02380 512800





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