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                                    
                                                                               
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       Legal & General Group Plc (L&G)     
the notification obligation: iii                                               
                                                                               
4. Full name of shareholder(s) (if                       N/A                   
different from 3.):iv                                                          
                                                                               
5. Date of the transaction and date                 18 April 2012              
on which the threshold is crossed or                                           
reached: v                                                                     
                                                                               
6. Date on which issuer notified:                   20 April 2012              
                                                                               
7. Threshold(s) that is/are crossed                L&G (below 3%)              
or reached: vi, vii                                                            

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

Class/type of      Situation               Resulting situation after          
shares             previous                     the triggering                
               to the triggering                  transaction                 
                  transaction                                                 
if possible                                                                   
using                    Number                 Number          % of voting   
the ISIN CODE   Number     of     Number          of             rights x     
                  of     Voting     of          voting                        
                Shares   Rights   shares        rights                        
                                                                              
                                  Direct    Direct  Indirect  Direct  Indirect
                                              xi      xii                     
                                                                              
Ordinary 5p        1,946,028                       Below 3%                   
                                                                              
                 (as on 23/01/                                                
                     2009)                                                    

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 financ Exercise Expiration Exercise/  Number of voting    % of voting   
     ial        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      
                                                                               
                                   Below 3%                                    

9. Chain of controlled undertakings through which the voting rights and/or the 
financial instruments are effectively held, if applicable: xxi                 
                                                                               
Legal & General Group Plc (Direct and Indirect) (Group)                        
                                                                               
Legal & General Investment Management (Holdings) Limited (LGIMH) (Direct and   
Indirect)                                                                      
                                                                               
Legal & General Investment Management Limited (Indirect) (LGIM)                
                                                                               
    Legal & General Group Plc (Direct) (L&G) (Below 3% = LGAS, LGPL & PMC)     
                                                                               
Legal & General Investment Management (Holdings) Limited (Direct) (LGIMHD)     
                                                                               
Legal & General Insurance Holdings Limited (Direct) (LGIH)                     
                                                                               
Legal & General Assurance (Pensions Management) Limited (PMC)                  
                                                                               
Legal & General Assurance Society Limited (LGAS & LGPL)                        
                                                                               
Legal & General Pensions Limited (Direct) (LGPL)                               

Proxy Voting:                                                                  
                                                                               
10. Name of the proxy holder:                             N/A                  
                                                                               
11. Number of voting rights proxy                         N/A                  
holder will cease to hold:                                                     
                                                                               
12. Date on which proxy holder will                       N/A                  
cease to hold voting rights:                                                   

13. Additional information:               Notification using the total voting  
                                              rights figure of 56,166,777      
                                                                               
14. Contact name:                       Susan Johnson-Brett (Company Secretary)
                                                                               
15. Contact telephone number:                        01865 393 200