Holding(s) in Company

TR-1: Notifications of Major Interests in Shares                               

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

2: Reason for notification (please tick the appropriate box or boxes)          
                                                                               
An acquisition or disposal of voting rights                                    
                                                                               
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 the   Hermes Equity Ownership Services    
notification                               Limited                             
                                                                               
obligation:iii                                                                 
                                                                               
4. Full name of shareholder(s) (if         Shares are held by the relevant     
different from 3.):iv                      custodian(s)                        
                                                                               
5. Date of the transaction (and date on    9 May 2012                          
which the threshold                                                            
                                                                               
is crossed or reached):v                                                       
                                                                               
6. Date on which issuer notified:          10 May 2012                         
                                                                               
7. Threshold(s) that is/are crossed or     0%                                  
reached:                                                                       

8: Notified Details                                                            
                                                                               
 A. Voting rights attached to shares                                           
                                                                               
  * Class/type of share If possible   GB0006650450                             
    use ISIN code                                                              
                                                                               
Situation previous to the triggering transaction                               
                                                                               
  * Number of shares                    * Number of voting rights              
                                                                               
1,871,352                             1,871,352                                
                                                                               
Resulting situation after the triggering transaction                           
                                                                               
  * Number of             Number of voting rights            Percentage of     
    shares                                                   voting rights     
                                                                               
                         Direct            Indirect       Direct     Indirect  
                                                                               
                                      17,570                       0.03128%    

 B. Qualifying Financial Instruments                                           
                                                                               
Resulting situation after the triggering transaction                           
                                                                               
    Type of       Expiration      Exercise/     No. of voting   Percentage of  
   financial         date        conversion    rights that may  voting rights  
  instrument                     period/date     be acquired                   
                                                   (if the                     
                                                 instrument                    
                                                 exercised/                    
                                                 converted)                    
                                                                               

Delta

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

Total (A+B+C)                                                                  
                                                                               
Number of voting rights                      Percentage of voting rights       
                                                                               
17,570                                       0.03128%                          

9. Chain of controlled undertakings through which the voting rights and/or the 
financial instruments are effectively held, if applicable:                     
                                                                               
BT Pension Scheme Trustees Limited, as trustee of the BT Pension Scheme        
("BTPS") controls Britel Fund Trustees Limited, which is the parent undertaking
of Hermes Fund Managers Limited ("HFML"). HFML is the parent undertaking of    
Hermes Equity Ownership Services Limited ("HEOS") (voting rights: 0.03128%)*   
                                                                               
* This notification is being made in respect of HEOS, which is an indirect     
holder of shares for the purpose of DTR 5.2.1(h) as a result of control of     
voting rights in relation to such shares.                                      

Proxy Voting:                                                                  
                                                                               
10. Name of the proxy holder:                See comment in Section 9          
                                                                               
11. Number of voting rights proxy holder     See comment in Section 9          
will cease to hold:                                                            
                                                                               
12. Date on which proxy holder will cease to See comment in Section 9          
hold voting rights:                                                            

13. Additional information:         This disclosure represents a cessation of  
                                    voting control only.                       
                                                                               
14. Contact name:                   Susan Johnson-Brett, Company Secretary     
                                                                               
15. Contact telephone number:       01865 393324