Holding(s) in Company

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

TR-1: Notifications of Major Interests in Shares                               

1. Identity of the issuer or the underlying issuer of existing                 
shares to which voting rights are attached:                                    
                                                                               
Serco Group plc                                                                
                                                                               
2. Reason for notification                                        [Yes/No]     
                                                                               
An acquisition or disposal of voting rights                         Yes        
                                                                               
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):                                                        
                                                                               
3. Full name of person(s) subject to     1 Lansdowne Partners Limited being the
notification                             General Partner of Lansdowne Partners 
obligation:                              Limited Partnership                   
                                                                               
                                         2 Lansdowne Partners International    
                                         Limited                               
                                                                               
4. Full name of shareholder(s) (if       Morstan Nominees Ltd (Registered      
different from 3):                       Shareholder)                          
                                                                               
5. Date of transaction (and date on      24 May 2010                           
which the                                                                      
threshold is crossed or reached if                                             
different):                                                                    
                                                                               
6. Date on which issuer notified:        26 May 2010                           
                                                                               
7. Threshold(s) that is/are crossed or   5%                                    
reached:                                                                       

8: Notified Details                                                            
                                                                               
A: Voting rights attached to shares                                            

Class/type of  Situation previous to          Resulting situation after         
shares            the triggering             the triggering transaction         
                    transaction                                                 
                                                                                
If possible    Number of  Number of   Number      Number of      Percentage of  
use              shares     voting      of      voting rights    voting rights  
ISIN code                   rights    shares                                    
                                                                                
                                              Direct  Indirect  Direct  Indirect
                                                                                
GB0007973794     below 5%   below 5%                 25,179,410            5.11%
                                                                                

B: Financial Instruments                                                       
                                                                               
Resulting situation after the triggering transaction                           

Type of          Expiration      Exercise/      No. of voting    Percentage of 
financial           date        conversion    rights that may be voting rights 
instrument                      period/date    acquired (if the                
                                                  instrument                   
                                                  exercised/                   
                                                  converted)                   
                                                                               

Total (A+B)                                                                    

Number of voting rights                 Percentage of voting rights            
                                                                               
25,179,410                              5.11%                                  

9. Chain of controlled undertakings through which the voting rights and /or the
financial instruments are effectively held, if applicable:                     
                                                                               
Lansdowne Partners International Limited is the parent undertaking of Lansdowne
Partners Limited                                                               

Proxy Voting:                                                                  
                                                                               
10. Name of proxy holder:           Lansdowne Partners Limited                 
                                                                               
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:         Serco Group plc is disclosing this         
                                    information in accordance with DTR 5.8.12  
                                                                               
14 Contact name:                    Sarah Howfield, Company Secretarial        
                                    Assistant                                  
                                                                               
15. Contact telephone name:         01256 744272                               

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

Note: Annex should only be submitted to the FSA not the issuer

Annex: Notification of major interests in shares                               

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