Inmarsat Regulatory News (ISAT)

TR-1: NOTIFICATION OF MAJOR INTEREST IN SHARESi

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

Inmarsat plc

2 Reason for the notification (please tick the appropriate box or boxes):

An acquisition or disposal of voting rights

An acquisition or disposal of qualifying financial instruments which may result in the acquisition of shares already issued to which voting rights are attached

An acquisition or disposal of instruments with similar economic effect to qualifying financial instruments

x

An event changing the breakdown of voting rights

Other (please specify):

Note that the reason for the notification was the disposal of 315,110 Inmarsat plc US$287,700,000 1.75% Convertible Bonds due 2017 on 8 October 2010, which left the notifier holding no such Convertible Bonds (after 677,485 were also disposed of on 7 October 2010) and resulted in total voting rights falling below the 14% threshold.

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

(a) Harbinger Capital Partners LLC, in its capacity as investment adviser to (i) Harbinger Capital Partners Master Fund I, Ltd. and (ii) Harbinger Capital Partners Special Situations Fund, L.P.

 (b) HGW GP, Ltd. as general partner of HGW Holding Company, L.P.

4. Full name of shareholder(s)  (if different from 3.):iv

(i) Harbinger Capital Partners Master Fund I, Ltd.; (ii) Harbinger Capital Partners Special Situations Fund, L.P.; and (iii) HGW Holding Company, L.P.

5. Date of the transaction and date on which the threshold is crossed or reached: v

8 October 2010

6. Date on which issuer notified:

13 October 2010

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

from above 14% to below 14%

8. Notified details:

A: Voting rights attached to shares viii, ix

Class/type of shares

if possible using the ISIN CODE

Situation previous to the triggering transaction

Resulting situation after the triggering transaction

Number of Shares

Number of Voting Rights

Number of shares

Number of voting rights

% of voting rights x

Direct

Direct xi

Indirect xii

Direct

Indirect

Ordinary Shares

64,277,349

64,277,349

64,277,349

64,277,349

13.95%

ISIN Code: GB00B09LSH68

B: Qualifying Financial Instruments

Resulting situation after the triggering transaction

Type of financial instrument

Expiration date xiii

Exercise/ Conversion Period xiv

Number of voting rights that may be acquired if the instrument is exercised/ converted.

% of voting rights

C: Financial Instruments with similar economic effect to Qualifying Financial Instruments xv, xvi

Resulting situation after the triggering transaction

Type of financial instrument

Exercise price

Expiration date xvii

Exercise/ Conversion period xviii

Number of voting rights instrument refers to

% of voting rights xix, xx

Inmarsat plc US$287,700,000 1.75% Convertible Bonds due 2017

USD 12.6940

16 November 2017

From 31 December 2007 to 9 November 2017

0

Nominal

Delta

0%

Total (A+B+C)

Number of voting rights

Percentage of voting rights

64,277,349

13.95%

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

Harbinger Capital Partners LLC serves as investment adviser to (i) Harbinger Capital Partners Master Fund I, Ltd. and (ii) Harbinger Capital Partners Special Situations Fund, L.P. The manager of Harbinger Capital Partners LLC is Harbinger Holdings, LLC, which is in turn controlled by Philip A. Falcone.

HGW GP, Ltd. is the general partner of HGW Holding Company, L.P. HGW GP, Ltd. is controlled by Philip A. Falcone.

Proxy Voting:

10. Name of the 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:

14. Contact name:

Peter A. Jenson, Vice President

15. Contact telephone number:

+1 212 339 5800