Independent Global Study Confirms IsatPhone Pro as the Ultimate Handheld Satellite Phone

IsatPhone Pro Performance and Features Compared to Iridium 9555 and Thuraya XT

LONDON, February 3, 2011 - An independent study of three latest-generation handheld satellite phones
has validated Inmarsat's claims for IsatPhone Pro, and concluded that it
outperforms the Iridium 9555 and Thuraya XT in a number of critical areas.

The global research programme, commissioned by Inmarsat, was conducted
over a two-month period in 16 locations around the world by TelAstra, Inc.,
an international telecommunications consultancy with extensive experience of
satellite communications. They undertook a fully-independent comparison study
of the three satellite phones using the six published claims made by Inmarsat
for IsatPhone Pro: global coverage; robust handset; clear voice quality;
reliable network connection; long battery life; and ease of use.

"All the satphones have pluses and minuses, and all of them would be
acceptable with various limitations," said Roger Rusch, TelAstra, Inc. "But
unquestionably, IsatPhone Pro is the best. It works everywhere and is the
most rugged. The voice quality is excellent, it has a reliable network
connection, and the longest battery life of the three satphones. It is also
easy to use.

"Although we were not asked to compare the price of the satphones or
satphone services, it appears that IsatPhone Pro prices are significantly
less expensive, and the service rates appear to be highly competitive as
well. IsatPhone Pro would be our choice regardless of affordability or any
other single issue," he said.

The comprehensive Satphone Comparison Study from TelAstra, Inc. provides
extensive data on the user experiences of two researchers and their
conclusions.

TelAstra, Inc. verified the global coverage of IsatPhone Pro, with
consistent performance in all 16 locations, from Anchorage to Zimbabwe. The
study also acknowledged the global coverage provided by Iridium, although it
noted frequent connection denials and disconnections. No claims of global
service are made for Thuraya XT.

In mechanical drop tests to measure the robustness of the three handsets,
IsatPhone Pro led the group; the only effect of half-metre and metre drops
was a loose battery cover, which was easily put back in place before
successfully making a call. The Thuraya XT experienced a damaged antenna,
while the Iridium 9555 suffered the most extreme damage, with a cracked case
and broken antenna, and was not functional after the drop tests.

Voice quality on IsatPhone Pro was frequently reported as clear and
"better than cellular". The Iridium 9555 provided similar voice quality under
the best conditions, but the study found that it sometimes offered "terrible
call quality". The researchers reported Thuraya XT's voice quality as
slightly inferior to the other two handsets even in the best conditions,
although not significant enough to be a factor.

The study found that the IsatPhone Pro took between 72 to 120 seconds to
obtain an GPS fix and make a call. For subsequent calls, and without the need
to get another GPS fix, IsatPhone Pro was ready for calls within 10 to 34
seconds. Thuraya XT also acquired very quickly, the study found.

The study found that the Iridium 9555 was ready for dialling within 31 to
40 seconds. However, while the availability of IsatPhone Pro and Thuraya XT
was essentially 100% during the entire testing programme, the researchers had
to wait for between 5 and 12 minutes to connect to the Iridium network on
several occasions.

Similarly, while IsatPhone Pro and Thuraya XT offered reliable
connections, the researchers experienced frequent dropped calls with the
Iridium 9555. They conclude that "it seems impossible to have an extended
call on Iridium 9555 without interruption… Our experience was that most of
the time the Iridium service is hit or miss".

In comparison, TelAstra, Inc. found IsatPhone Pro to be "remarkably
stable". The researchers commented in the report: "We routinely talked while
walking around Palos Verdes, Los Angeles, for 20 minutes or more. We had two
1.5-hour and one 2.5-hour uninterrupted stationary calls during the battery
capacity tests."

Tests on the battery life of the three handsets showed that IsatPhone Pro
had the longest talk time and stand-by time, with measured talk time of 7
hours 45 minutes (against a published claim of 8 hours) and measured stand-by
time of 84 hours (against a published claim of 100 hours). This compared to a
talk time of 5 hours 6 minutes, and stand-by time of 30 hours, for the
Iridium 9555; and talk time of 6 hours 19 minutes, and stand-by time of 38
hours 30 minutes, for the Thuraya XT.

The study looked at a range of areas to assess the phones' ease of use.
It found that, while the keypads of IsatPhone Pro and Iridium 9555 were large
enough to use while wearing gloves - essential in certain environments - the
smaller keypad of the Thuraya XT was more likely to cause input errors. The
researchers found that all screens were difficult to read in bright sunlight;
in dim light, the monochrome screen of the Iridium 9555 was the hardest to
read. The study found that all handsets were convenient to hold while talking
or walking.

"We know that satellite phone users apply these six criteria when judging
a service, which is why we designed IsatPhone Pro to perform well in these
areas," said Drew Brandy, Director of Land Business at Inmarsat. "We were
highly confident that we were offering the market leading service, but the
hard facts of this independent study now confirm it. This is an extensive
piece of research, conducted globally, and it validates all of our claims."

A video interview with Roger Rusch, detailing the research programme and
explaining the findings, is available at YouTube (bit.ly/satcomp).

The Satphone Comparison Study report can be downloaded from the Inmarsat
web site (HTTP://www.inmarsat.com/comparison).

Notes to Editors

The research programme was undertaken by Roger Rusch and Charles Emmert
of TelAstra, Inc., veterans of the satellite communications industry, in late
2010.

They visited 16 locations: Finland (Helsinki and Kaustinen); Italy
(Lake Como, Milan and Rome); Japan (Tokyo); Singapore; South Africa
(Johannesburg); United Arab Emirates (Dubai); United Kingdom (London); United
States of America (Anchorage, Fairbanks, Los Angeles, New York and West Palm
Beach); Zimbabwe (Victoria Falls).

About Inmarsat

Inmarsat plc (LSE: ISAT) is the leading provider of global
mobile satellite communications services. Since 1979, Inmarsat has been
providing reliable voice and high-speed data communications to governments,
enterprises and other organizations, with a range of services that can be
used on land, at sea or in the air. The company's services are delivered
through a global network of more than 400 distribution partners and service
providers operating in 100 countries. For the year ended 31 December 2009,
Inmarsat plc had total revenue of US$1,038.1 million (2008: US$996.7 million)
with an EBITDA of US$594.2 million (2008: US$531.2 million). For more
information, please visit www.inmarsat.com .

Media Contact: John Warehand, PR Manager, Inmarsat, Tel No: +44-20-7728-1579, Mob: +44-7739-778128, Email: john_warehand at inmarsat.com