Inmarsat Regulatory News (ISAT)

Inmarsat Plc ("Inmarsat" or the "Company")

Publication of the 2017 Annual Report and 2018 Annual General Meeting Notice

Inmarsat will today publish and post to shareholders its Annual Report for the year ended 31 December 2017 (the 'Annual Report'), together with its 2018 Annual General Meeting Notice (the 'Notice') with related explanatory circular (the 'Circular') (together the 'AGM Notice and Circular').

In addition to the regular AGM business, the AGM Notice and Circular contains a proposed resolution which will be put to shareholders at the AGM to rectify a procedural issue of which the Board of Inmarsat have become aware regarding the omission of filing interim accounts to support the payment of a number of historical dividends by the Company (the 'Relevant Distributions').

In order to remedy this, the proposed resolution will, if passed, ratify the Relevant Distributions and give the Board authority to enter into deeds of release for shareholders and directors and restore all parties to the position they were intended to be in had filings been made for the Relevant Distributions in accordance with the procedural requirements of the Companies Act 2006. This is in line with the remedies taken by other listed companies that have encountered similar procedural issues in the past. The issue is of a historical nature and there is no change to the financial outlook of the Company and no past accounts will need to be restated. No fines or other penalties have been incurred by the Company. There is no impact on the final dividend proposed for approval by shareholders at the AGM.

The Circular, which was approved today by the UK Listing Authority, contains further details of the Relevant Distributions. The Notice, which accompanies the Circular, convenes the Annual General Meeting of the Company for 10.00am on 2 May 2018 at 99 City Road, London, EC1Y 1AX.

The Annual Report and the AGM Notice and Circular is available at investors.inmarsat.com .

In accordance with Listing Rule 9.6.1, an electronic copy of the Annual Report, the AGM Notice and Circular and form of proxy will be submitted to the National Storage Mechanism and should be available shortly for inspection at www.morningstar.co.uk/uk/NSM

The information set out in the Appendix, which is extracted from the Annual Report, should be read in conjunction with the Final Results Announcement released on 9 March 2018, which includes a condensed set of consolidated financial statements for the year ended 31 December 2017, an indication of the important events that have occurred in the reporting period and a description of Inmarsat's principal risks and uncertainties. That information, together with the information set out in the Appendix, constitutes the material required by Disclosure Guidance and Transparency Rule 6.3.5 which is required to be communicated to the media in full unedited text through a Regulatory Information Service. This announcement is not a substitute for reading the full Annual Report. Page and note references in the Appendix are page and note numbers in the Annual Report and Notes to the Financial Statements.

Alison Horrocks

Company Secretary

+44 20 7728 1626

Appendix

DIRECTORS' RESPONSIBILITY STATEMENT

The Directors are responsible for preparing the Annual Report and the financial statements in accordance with applicable law and regulations.

Company law requires the Directors to prepare such financial statements for each financial year. Under that law the Directors are required to prepare the Group financial statements in accordance with International Financial Reporting Standards ('IFRS') as adopted by the European Union and Article 4 of the IAS Regulation and have also chosen to prepare the Parent Company financial statements in accordance with Financial Reporting Standard 101 Reduced Disclosure Framework. Under company law the Directors must not approve the financial statements unless they are satisfied that they give a true and fair view of the state of affairs of the Company and of the profit or loss of the Company for that period.

In preparing the Parent Company financial statements, the Directors are required to:

§ select suitable accounting policies and then apply them consistently

§ make judgements and accounting estimates that are reasonable and prudent

§ state whether Financial Reporting Standard 101 Reduced Disclosure Framework has been followed, subject to any material departures disclosed and explained in the financial statements and

§ prepare the financial statements on the going concern basis unless it is inappropriate to presume that the Company will continue in business

RELATED PARTY TRANSACTIONS

In the normal course of operations the Group engages in transactions with its equity-owned investees Navarino UK and JSAT Mobile Communications Inc. These transactions represent sales of airtime and equipment and are measured at the amounts exchanged. Group revenue from the related parties for the 2017 financial year was $38.1m and $16.9m, respectively (2016: $33.1m and $18.2m, respectively). The amount receivable from the related parties at 31 December 2017 was $12.6m and $1.7m, respectively (2016: $9.3m and $1.8m, respectively).

Amounts owing to the Executive as at 31 December 2017 and 2016 were $1.2m and relate to remuneration earned in the normal course of operations (see note 8 of the Annual Report).