Cheshire, UK -- (MARKET WIRE) -- February 26, 2007 --

                                 Protherics PLC



                    Notification of Major Interest in Shares





London, UK; Brentwood, TN, US; 26 February 2007 - Protherics PLC ("Protherics"
or the "Company"), the international biopharmaceutical company focused on
critical care and cancer, announces that the following notification of interest
in the ordinary share capital of the Company was received on 23 February 2007
from AMVESCAP PLC.




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


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):___________________________________________

2. Full name of person(s) subject to the                              AMVESCAP PLC
notification obligation:

3. Full name of shareholder(s) (if different from 2.):

4. Date of the transaction (and date on which the                   20 February 2007
threshold is crossed or reached if different):

5. Date on which issuer notified:                                   21 February 2007

6. Threshold(s) that is/are crossed or reached:                           10%


7. Notified details:




A: Voting rights attached to shares
Class/type of     Situation previous to    Resulting situation after the triggering transaction
shares            the Triggering
                  transaction
if possible using Number of   Number of    Number of     Number of voting rights     % of voting rights
the ISIN CODE     Shares      Voting       shares
                              Rights       Direct        Direct        Indirect      Direct    Indirect
Ordinary Shares   30,886,678  30,886,678   35,740,354                  35,740,354              10.54%
2p
GB0007029209




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
35,740,354                                        10.54%




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

Chase Nominees  -  7,520,443

Vidacos Nominees  -  28,104,599

Northern Trust Company (London)  -  115,312




Proxy Voting:

9. Name of the proxy holder:

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

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


12. Additional information:





                                   |  Ends  |





For further information please contact:


Protherics
Nick Staples, Director of Corporate Affairs                                     +44 (0) 7919  480510
Julie Vickers, Company Secretary                                                +44 (0)1928 518010

Financial Dynamics - press enquiries
London: Ben Atwell, Anna Keeble                                                 +44 (0) 20 7831 3113
New York: John Capodanno, Jonathan Birt                                         +1 212 850 5600



Or visit  www.protherics.com




                      This information is provided by RNS
            The company news service from the London Stock Exchange