Holding(s) in Company

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     AXA S.A, 25 Avenue Matignon, 75008    
notification                             Paris and its group of companies      
obligation:                                                                    
                                                                               
4. Full name of shareholder(s) (if                                             
different from 3):                                                             
                                                                               
5. Date of transaction (and date on      20 September 2010                     
which the                                                                      
threshold is crossed or reached if                                             
different):                                                                    
                                                                               
6. Date on which issuer notified:        21 September 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  24,283,163 24,283,163        0      0 25,014,481    0.00     5.07
                                                                               

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            
                                                                               
25,014,481                              5.07%                                  

9. Chain of controlled undertakings through which the voting rights and /or the
financial instruments are effectively held, if applicable:                     
                                                                               
Name of the Company/Fund Number of Shares % of issued share capital            
                                                                               
Alliance Bernstein 405,227.00 0.082212                                         
                                                                               
Indirect                                                                       
                                                                               
Alliance Capital Management 1,047,445.00 0.212504                              
                                                                               
Indirect                                                                       
                                                                               
AXA Australia 44,040.00 0.008935                                               
                                                                               
Indirect                                                                       
                                                                               
AXA Financial, Inc 23,221,435.00 4.711133                                      
                                                                               
Indirect                                                                       
                                                                               
AXA France 296,334.00 0.060120                                                 
                                                                               
Indirect                                                                       
                                                                               
Total Direct 0 0.00000                                                         
                                                                               
Total Indirect 25,014,481 5.07490                                              
                                                                               
TOTAL 25,014,481 5.07490                                                       

Proxy Voting:                                                                  
                                                                               
10. Name of 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:         Serco Group plc is disclosing this i       
                                    nformation in accordance with DTR 5.8.12   
                                                                               
14 Contact name:                    Chris Winters, Assistant Company Secretary 
                                                                               
15. Contact telephone name:         01256 744108