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     Invesco Limited                       
notification                                                                   
obligation:                                                                    
                                                                               
4. Full name of shareholder(s) (if       N/A                                   
different from 3):                                                             
                                                                               
5. Date of transaction (and date on      24 August 2012                        
which the                                                                      
threshold is crossed or reached if                                             
different):                                                                    
                                                                               
6. Date on which issuer notified:        28 August 2012                        
                                                                               
7. Threshold(s) that is/are crossed or   5%, 10%                               
reached:                                                                       

8: Notified Details                                                            
                                                                               
A: Voting rights attached to shares                                            

Class/type   Situation previous to          Resulting situation after          
of              the triggering              the triggering transaction         
shares            transaction                                                  
                                                                               
If possible  Number of  Number of  Number of     Number of       Percentage of 
use            shares     voting    shares     voting rights     voting rights 
ISIN code                 rights                                               
                                                                               
Ord 2p       24,803,084 24,803,084           Direct   Indirect  Direct Indirect
                                                                               
                                                     49,961,897         10.02% 

B: Qualifying 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)                   
                                                                               

NominalDelta

C: Financial Instruments with similar economic effect to Qualifying Financial  
Instruments                                                                    
                                                                               
Resulting situation after the triggering transaction                           
                                                                               
Type of    Exercise  Expiration Exercise/  Number of voting   % of voting      
financial  price     date       Conversion rights instrument  rights           
instrument                      period     refers to                           
                                                                               

Total (A+B+C)                                                                  

Number of voting rights                 Percentage of voting rights            
                                                                               
49,961,897                              10.02%                                 

9. Chain of controlled undertakings through which the voting rights and /or the
financial instruments are effectively held, if applicable:                     
                                                                               
Invesco Canada Ltd & Invesco Advisers Inc - 17,844                             
                                                                               
Invesco Asset Management GmbH - 40,441                                         
                                                                               
Invesco Asset Management Dublin - 116,077                                      
                                                                               
Invesco Asset Management Japan - 56,296                                        
                                                                               
Invesco Asset Management Ltd - 18,239,871                                      
                                                                               
Invesco Asset Management Ltd & Invesco Advisers Inc. - 12,149                  
                                                                               
Invesco PowerShares Capital Management LLC - 41,570                            
                                                                               
Invesco PowerShares Capital Management Ireland - 407                           
                                                                               
Invesco Fund Managers Ltd - 31,437,242                                         

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