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       Proxy Voting                                          X    
specify):                                                                      

3. Full name of person(s) subject to    BT Pension Scheme Trustees Limited as  
the notification obligation: iii        trustee of the BT Pension Scheme. See  
                                         Section 9 for further information.    
                                                                               
4. Full name of shareholder(s) (if                       N/A                   
different from 3.):iv                                                          
                                                                               
5. Date of the transaction and date                 20 June 2011               
on which the threshold is crossed or                                           
reached: v                                                                     
                                                                               
6. Date on which issuer notified:                   21 June 2011               
                                                                               
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          voting            rights x     
the ISIN CODE  Shares    Voting    shares        rights                         
                         Rights                                                 
                                                                                
                                   Direct   Direct  Indirect   Direct   Indirect
                                              xi       xii                      
                                                                                
0665045       2,911,738 2,911,738   n/a      n/a    2,661,727    n/a     4.822% 
                                                                                
GB0006650450                                                                    
                                                                                
ORD 5p                                                                          
                                                                                
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      
                                                                               
               2,661,727                                4.822%                 

9. Chain of controlled undertakings through which the voting rights and/or the 
financial instruments are effectively held, if applicable: xxi                 
                                                                               
BT Pension Scheme Trustees Limited, as trustee of the BT Pension Scheme        
("BTPS") is the parent undertaking of Britel Fund Nominees Limited and Britel  
Fund Trustees Limited, which is the parent undertaking of Hermes Fund Managers 
Limited ("HFML"). HFML is the parent undertaking of:-                          
                                                                               
1. Hermes Equity Ownership Services Limited ("HEOS") (voting rights held in    
this issuer: 4.822%)*                                                          
                                                                               
* This notification is also being made in respect of HEOS, which is an indirect
holder of shares for the purpose of DTR 5.2.1(h). The voting rights include the
following: (i) all of the voting rights of the underlying clients of HEOS for  
whom it provides voting services; (ii) all of the voting rights attaching to   
the direct shareholding of BTPS; (iii) all of the voting rights attaching to   
shares managed by HIML; and (iv) the voting rights attaching to the direct     
shareholding of BTPS that are managed by HSL.                                  
                                                                               
Please see Section 13 for further information.                                 

Proxy Voting:                                                                  
                                                                               
10. Name of the proxy holder:                 See comment in Section 13.       
                                                                               
11. Number of voting rights proxy             See comment in Section 13.       
holder will cease to hold:                                                     
                                                                               
12. Date on which proxy holder will           See comment in Section 13.       
cease to hold voting rights:                                                   

13. Additional information:               HEOS hold the voting rights under a  
                                        standing proxy contained in agreements 
                                        for the provision of voting services to
                                          various underlying clients for the   
                                            purposes of DTR 5.2.1(h), which    
                                           includes all of the shares owned    
                                          directly by BTPS, all of the voting  
                                         rights attaching to shares managed by 
                                        HIML and the voting rights attaching to
                                         the direct shareholding of BTPS that  
                                                  are managed by HSL           
                                                                               
                                        All voting rights held on behalf of the
                                         above entities are aggregated for the 
                                               purposes of DTR 5.2.1(e).       
                                                                               
                                         This disclosure is made by BT Pension 
                                         Scheme Trustees Limited as trustee of 
                                          the BT Pension Scheme, which is the  
                                          ultimate parent undertaking for the  
                                               purposes of DTR 5.2.1(e).       
                                                                               
14. Contact name:                       Susan Johnson-Brett, Company Secretary,
                                                                               
                                                Oxford Instruments plc         
                                                                               
15. Contact telephone number:                        01865 393324              

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.