PTIL Protherics (MM)

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

An acquisition or disposal 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): INCREASE IN NUMBER OF VOTING
SHARES IN ISSUE

√

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

Aviva plc & its subsidiaries 

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

Registered Holder:

BNY Norwich Union
Nominees Limited     
  6,033,442*

Chase GA Group
Nominees Limited  
19,592,672*

Chase Nominees Limited
881,559*

CUIM Nominee Limited
4,416,028*

Vidacos Nominees Limited
65,125*

*denotes direct interest  

BNP Paribas - London
636,429

Chase Nominees Limited 
3,171,774

State Street Nominees Limited  
9,428,137

Vidacos Nominees
Limited 
1,746,000    

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

27 October 2008

5. Date on which issuer notified:

28 October 2008

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

9% to 8% Change at Direct Interest level   

7. 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

GB0007029209

   
     46,722,061    

     46,722,061    

     30,988,826    

   
     30,988,826    

     14,982,340    

   
     8.84%    

     4.28%    

B: Financial Instruments

Resulting situation after the triggering transaction 

Type of financial
instrument  

     Expiration    
     date 

     Exercise/
     Conversion Period/    
     Date  

     Number of voting
     rights that may be
     acquired if the
     instrument is exercised/    
     converted. 

     % of voting    
     rights

N/A

Total (A+B)

Number of voting rights    

     % of voting rights

   
45,971,166

   
     13.12%

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

The voting rights are managed and controlled by Aviva Investors Global Services Limited, with the
following chain of controlled undertakings:-

Aviva Investors Global Services Limited:

• Aviva plc (Parent Company)

• Aviva Group Holdings Limited (wholly owned subsidiary of Aviva plc)

• Aviva Investors Holdings Limited (wholly owned subsidiary of Aviva Group Holdings Limited)

• Aviva Investors Global Services Limited (wholly owned subsidiary of Aviva Investors Holdings Limited)
  

Proxy Voting:

9. Name of the proxy holder:

   
See Section 3

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:

                        Figures are based on a revised total number of
                        voting rights of 340,427,481

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, Lara Mott

                         +44 (0) 20 7831 3113 

New York: John Capodanno

                         +1 212 850 5600