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     Capital Research and Management Compan
notification                             y                                     
obligation:                                                                    
                                                                               
4. Full name of shareholder(s) (if                                             
different from 3):                                                             
                                                                               
5. Date of transaction (and date on      16 February 2011                      
which the                                                                      
threshold is crossed or reached if                                             
different):                                                                    
                                                                               
6. Date on which issuer notified:        17 February 2011                      
                                                                               
7. Threshold(s) that is/are crossed or   Above 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 of      Number of      Percentage of  
use             shares     voting     shares     voting rights    voting rights  
ISIN code                  rights                                                
                                                                                 
                                               Direct  Indirect  Direct  Indirect
                                                                                 
0797379       21,748,000 21,748,000 25,049,264        25,049,264          5.0783%
                                                                                 

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            
                                                                               
25,049,264                              5.0783%                                

9. Chain of controlled undertakings through which the voting rights and /or the
financial instruments are effectively held, if applicable:                     
                                                                               

Proxy Voting:                                                                  
                                                                               
10. Name of 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:         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.