RNS Number:4154P
Marconi Corporation PLC
04 September 2003


The company received the following notification today:

                                                              Aviva plc
                                                              P O Box 89
                                                              Surrey Street
                                                              Norwich NR1 3DR

                                                              3 September 2003

The Company Secretary
Marconi Corporation plc
4th Floor
Regents Place
338 Euston Road
London
NW1 3BT


Dear Sir,

Marconi Corporation plc (The "company") - SEDOL 3280069

This notification supersedes our previous notification to you dated 29 August
2003 and is prompted by purchases totalling 3,200,000 on 2 September 2003.

This notification relates to issued ordinary shares of 5p each in the capital of
the company (the "Shares") and is given in fulfilment of the obligations imposed
by sections 298 to 202 of the Companies Act 1985 (the "Act").


1.   Notification on behalf of Morley Fund Management Limited (a
subsidiary of Aviva plc).

1.1  We hereby notify you on behalf of Morley Fund Management
Limited that immediately after the time when the obligation to make this
notification arose Morley Fund Management Limited were interested in 50,985,017
shares.

1.2  The identity of the registered holders of the shares to which this
notification relates and the number of shares held by each of them are set out
in the attached Appendix: Morley Fund Management Limited.

2.   Notification on behalf of Aviva plc.

2.1  We hereby notify you on behalf of Aviva plc that immediately
after the time when the obligation to make this notification arose Aviva plc
were interested in 50,985,017 shares giving the Aviva group a total percentage
interest in the shares of 5.10%.

2.2  The identity of the registered holders of the shares to which
this notification relates and the number of shares held by each of them are set
out in the attached Appendix: Aviva plc.


If you require further information as to which companies in the Aviva group hold
interests in the shares (by virtue of s.203 of the Act) please submit a written
request and we will be happy to supply this information.

We are only required to notify interests which are defined as material interests
when the holding is equal to 3% or more of the Company's relevant share capital.
The term material interests exclude certain categories where we do not hold a
beneficial interest, for example where the shares are held in an Authorised unit
Trust Scheme or Open Ended Investment Company.  Holdings in those categories are
therefore not included in the holding notified under this letter.  If you wish
us to confirm the level of holdings in these categories, please let us know.



Yours faithfully,

Diane Thirkettle
For and on behalf of
Aviva plc

The Company Secretary                                       3 September 2003
Marconi Corporation plc



APPENDIX: MORLEY FUND MANAGEMENT LIMITED

REGISTERED HOLDERS                                        NUMBER OF SHARES HELD

BNY Norwich Union Nominees Ltd                            15,551,986 (Material)
Chase GA Group Nominees Ltd                               25,177,612 (Material)
CUIM Nominee Ltd                                          10,255,419 (Material)



TOTAL PERCENTAGE INTEREST OF MORLEY FUND MANAGEMENT LIMITED: 5.10%
ISSUE SHARE CAPITAL ON WHICH THIS NOFIICATION IS BASED : 1,000,000,000



The Company Secretary                                       3 September 2003
Marconi Corporation plc



APPENDIX: AVIVA PLC

REGISTERED HOLDERS                                        NUMBER OF SHARES HELD

BNY Norwich Union Nominees Ltd                            15,551,986 (Material)
Chase GA Group Nominees Ltd                               25,177,612 (Material)
CUIM Nominee Ltd                                          10,255,419 (Material)



TOTAL PERCENTAGE INTEREST OF MORLEY FUND MANAGEMENT LIMITED: 5.10%
ISSUE SHARE CAPITAL ON WHICH THIS NOFIICATION IS BASED : 1,000,000,000




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