1.

Name of the issuer

Inmarsat plc

2.

State whether the notification relates to (i) a

transaction notified in accordance with DTR 3.1.2 R

3.

Name of person discharging managerial

responsibilities

Leo Mondale

4.

State whether notification relates to a person

connected with a person discharging managerial responsibilities/director named in 3 and identify the connected person

Person named in 3.

5.

Indicate whether the notification is in respect of a holding of the person referred to in 3 or 4 above or in respect of a nonbeneficial

interest 1

Person named in 3.

6.

Description of shares (including class), debentures or derivatives or financial instruments relating to shares

Ordinary shares of Euro 0.0005 each

7.

Name of registered shareholders(s) and, if more than one, the number of shares held by each of them

Greenwood Nominees Limited A/C 473968

8.

State the nature of the transaction

Sale of shares

9.

Number of shares, debentures or financial

instruments relating to shares acquired

N/A

10.

Percentage of issued class acquired (treasury shares of that class should not be taken into account when calculating percentage)

N/A

11.

Number of shares, debentures or financial

instruments relating to shares disposed

100,000

12.

Percentage of issued class disposed (treasury shares of that class should not be taken into account when calculating percentage)

0.02%

13.

Price per share or value of transaction

510.6783p per share

14.

Date and place of transaction

2 September 2008

15.

Total holding following notification and total percentage holding following notification (any treasury shares should not be taken into account when calculating percentage)

16.

Date issuer informed of transaction

106,831

0.2%

2 September 2008 

Name of authorised official of issuer responsible for making notification: Alison Horrocks

Date of notification : 2 September 2008