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

X

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):

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

BlackRock, Inc.

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

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

5th October 2010

6. Date on which issuer notified:

7th October 2010

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

Holding has gone above 12%

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

GB00B09LSH68

42,576,471

42,576,471

N/A

N/A

49,458,944

N/A

10.74%

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

CFD

N/A

N/A

N/A

7,958,250

Nominal

Delta

1.73%

1.73%

Total (A+B+C)

Number of voting rights

Percentage of voting rights

57,417,194

12.47%

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

BlackRock Investment Management (UK) Limited - 57,417,194 (12.47%)

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:

BlackRock Threshold Reporting Team

14. Contact name:

Stuart Watchorn

15. Contact telephone number:

020 7743 5741; stuart.watchorn@blackrock.com

Note: Annex should only be submitted to the FSA not the issuer

Annex: Notification of major interests in share

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

Full name

(including legal form of legal entities)

BlackRock, Inc.

Contact address

(registered office for legal entities)

33 King William Street, London, EC4R 9AS

Phone number & email

020 7743 5741; stuart.watchorn@blackrock.com

Other useful information

(at least legal representative for legal persons)

Stuart Watchorn

B: Identity of the notifier, if applicable

Full name

Contact address

Phone number & email

Other useful information

(e.g. functional relationship with the person or legal entity subject to the notification obligation)

C: Additional information

For notes on how to complete form TR-1 please see the FSA website.