Holding(s) in Company

For filings with the FSA include the                                           
annex                                                                          
                                                                               
For filings with issuer exclude the                                            
annex                                                                          

TR-1: NOTIFICATION OF MAJOR INTEREST IN SHARESi                                

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

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    GAM INTERNATIONAL MANAGEMENT LIMITED   
the notification obligation: iii                                               
                                                 GAM UK DIVERSIFIED            
                                                                               
4. Full name of shareholder(s) (if                                             
different from 3.):iv                                                          
                                                                               
5. Date of the transaction and date                11 August 2010              
on which the threshold is crossed or                                           
reached: v                                                                     
                                                                               
6. Date on which issuer notified:                  12 August 2010              
                                                                               
7. Threshold(s) that is/are crossed                      4%                    
or reached: vi, vii                                                            

8. Notified details:
A: Voting rights attached to shares viii, ix

Class/type of Situation previous            Resulting situation after           
shares         to the triggering                  the triggering                
                  transaction                      transaction                  
                                                                                
if possible    Number    Number    Number       Number of         % of voting   
using            of        of     of shares       voting           rights x     
the ISIN CODE  Shares    Voting                   rights                        
                         Rights                                                 
                                                                                
                                   Direct   Direct xi Indirect  Direct  Indirect
                                                        xii                     
                                                                                
ORDINARY      2,197,152           1,897,152 1,897,152           3.84%           
                                                                                
B: Qualifying Financial Instruments                                             
                                                                                
Resulting situation after the triggering transaction                            
                                                                                
Type of financial Expiration     Exercise/       Number of voting   % of voting 
   instrument     date xiii  Conversion Period  rights that may be    rights    
                                    xiv          acquired if the                
                                                  instrument is                 
                                                    exercised/                  
                                                    converted.                  
                                                                                

C: Financial Instruments with similar economic effect to Qualifying Financial   
Instruments xv, xvi                                                             
                                                                                
Resulting situation after the triggering transaction                            
                                                                                
   Type of     Exercise Expiration Exercise/  Number of voting    % of voting   
  financial     price   date xvii  Conversion rights instrument  rights xix, xx 
  instrument                         period       refers to                     
                                     xviii                                      
                                                                                
                                                                Nominal   Delta 
                                                                                

Total (A+B+C)                                                                  
                                                                               
        Number of voting rights               Percentage of voting rights      
                                                                               
               1,897,152                                 3.84%                 

9. Chain of controlled undertakings through which the voting rights and/or the 
financial instruments are effectively held, if applicable: xxi                 
                                                                               
GAM INTERNATIONAL MANAGEMENT LIMITED'S POSITION IS HELD IN GAM UK DIVERSIFIED  

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:                              None                  
                                                                               
14. Contact name:                                    Barbara Hall              
                                                                               
15. Contact telephone number:                        020 7917 2356             

Note: Annex should only be submitted to the FSA not the issuer                 
                                                                               
Annex: Notification of major interests in sharesxxii                           

A: Identity of the persons or legal entity subject to the notification
obligation

Full name                                                                      
(including legal form of legal                                                 
entities)                                                                      
                                                                               
Contact address                                                                
(registered office for legal entities)                                         
                                                                               
Phone number & email                                                           
                                                                               
Other useful information                                                       
(at least legal representative for                                             
legal persons)                                                                 

B: Identity of the notifier, if applicable

Full name                                                                      
                                                                               
Contact address                                                                
                                                                               
Phone number & email                                                           
                                                                               
Other useful information(e.g.                                                  
functional relationship with the person                                        
or legal entity subject to the                                                 
notification obligation)                                                       

C: Additional information                                                      
                                                                               

For notes on how to complete form TR-1 please see the FSA website.