Holding(s) in Company

Pennon Group PLC
26 November 2007

PENNON GROUP PLC

FOR IMMEDIATE RELEASE

HOLDING IN COMPANY


NOTIFICATION OF MAJOR INTERESTS IN SHARES



1.     Identity of the issuer or the underlying issuer of existing shares to
which voting rights are attached:


        PENNON GROUP PLC


2.     Reason for the notification


        An acquisition of voting rights


3.     Full name of person(s) subject to the notification obligation


        Standard Life Investments Ltd


4.     Full name of shareholder(s)


        Vidacos Nominees


5.     Date of the transaction (and date on which the threshold is crossed or
reached if different)


        22 November 2007


6.     Date on which issuer notified:


        23 November 2007


7.     Threshold(s) that is/are crossed or reached:


8.     Notified details:   5%


A:    Voting rights attached to shares


Class/type of shares if possible              Situation previous to the Triggering transaction
using the ISIN CODE
                                  Number of shares                   Number of voting Rights

GB00B18V8630                      15,946,939                               15,946,939



Resulting situation after the triggering transaction


Class/type of shares if      Number of shares          Number of voting rights (ix)  % of voting rights
possible using the ISIN CODE
                             Direct                    Direct (x)    Indirect (xi)   Direct      Indirect


 GB00B18V8630                17,835,484                13,170,793    4,664,691       3.777       1.338



B:    Financial Instruments

        Resulting situation after the triggering transaction


Type of         Expiration Date       Exercise/Conversion       Number of voting rights     % of voting rights
financial       (xiii)                Period/ Date              that may be acquired if the
instrument                                                      instrument is exercised/
                                                                converted.


N/A


Total (A+B)
Number of voting rights        % of voting rights

17,835,484                     5.115%



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



Standard Life Investments Ltd



Proxy Voting:



10. Name of the proxy holder:


  N/A


11.  Number of voting rights proxy holder will cease to hold:


        N/A


12. Date on which proxy holder will cease to hold voting rights:


        N/A


13. Additional information:





        Annex to Notification of Major Interests In Shares



A:    Identity of the person or legal entity subject to the notification
obligation


Full name (including legal form for legal entities):



                Pennon Group Plc

Contact address (registered office for legal entities):


Peninsula House, Rydon Lane, Exeter, Devon, EX2 7HR

Contact name    Christopher Paul Richards - Interim Assistant Company Secretary

Phone number   01392 443060



26 November 2007

www.pennon-group.co.uk

End transmission


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