Cable&Wireless Worldwide Signs Five Year Partnership Deal With SONI (System Operator for Northern Ireland)

BELFAST and LONDON, May 5, 2011 - Cable&Wireless Worldwide today announces it has renewed and
extended its contract to manage the Operational Telecoms Network used by
System Operator for Northern Ireland (SONI) following an open competitive
tendering process. In addition to existing work, Cable&Wireless Worldwide
will connect planned wind farms to the grid.

As Transmission System Operator (TSO) in Northern Ireland,
SONI ensures the safe, secure, reliable and economic operation of the
electricity transmission grid in Northern Ireland. In co-operation with
EirGrid, SONI also administrate the wholesale Single Electricity Market for
the island of Ireland through SEMO.

With the uninterrupted provision of electricity being
paramount, it is vital that SONI's mission critical services delivered on the
Operational Telecoms Network are always available, as any downtime could have
a direct impact on services to electricity customers in Northern Ireland.

Commenting on the contract being awarded to Cable&Wireless
Worldwide, Nick Fullerton, Commercial Manager, SONI said: "The security and
integrity of the Operational Telecoms Network is critical to the SONI
business. The fact that Cable&Wireless Worldwide did not have one single
outage during seven years of the previous contract is testimony to the skills
and expertise of their engineers and systems."

Cable&Wireless Worldwide provides 24/7 management of the
Operational Telecoms Network and has a team of dedicated engineers
continually monitoring the network and maintaining its operation. Well known
for its highly resilient systems that operate under the most arduous
conditions, Cable&Wireless Worldwide works with many of the world's top
utilities. This contract win was secured through a full OJEU procurement
process, and will also see Cable&Wireless Worldwide deliver a full voice and
data infrastructure, including the roll out of IP Telephony to SONI's control
room and all SONI sites.

Sean Mahon, Managing Director, Enterprise, for Europe, Middle
East & Africa, Cable&Wireless Worldwide, added: "Our partnership with SONI is
an excellent endorsement of the skills and expertise within Cable&Wireless
Worldwide and the mission critical services we offer. We understand the
implications of a failure on the Operational Telecoms Network and have
developed a highly flexible system that allows us to upscale, should the
network come under pressure at certain times; such as inclement weather
conditions. The public can rest assured that they have SONI and
Cable&Wireless Worldwide working together to ensure the continued supply of
electricity throughout Northern Ireland, whatever the conditions."

Notes to Editors

For more information about Cable&Wireless Worldwide, please
visit www.cw.com

About SONI

SONI are a wholly owned subsidiary of EirGrid plc, the Transmission
System Operator (TSO) for the Republic of Ireland. Based in Belfast, SONI
ensure the safe, secure, reliable and economic operation of the high voltage
electricity grid in Northern Ireland and in cooperation with EirGrid

SONI also administrate the wholesale Single Electricity Market (SEM) for
the island of Ireland.

About Cable&Wireless Worldwide

Cable&Wireless Worldwide (LSE: CW.) aims to be the
first-choice provider of mission critical communications for large users of
telecoms. Cable&Wireless Worldwide is one of the world's leading critical
communication companies, providing a range of high-quality managed voice,
data and IP-based services and applications to large corporates,
multinational companies, governments, carrier customers and resellers across
Ireland, the UK, Asia Pacific, India, Middle East & Africa, Continental
Europe and North America.

Cable&Wireless Worldwide is the first company to offer access
to a Next Generation Network (NGN) in either Northern Ireland or the Republic
of Ireland. This NGN, stretching to over 500,000km across the World, allows
customers access to Cable&Wireless Worldwide's Multi-Service Platform (MSP)
providing highly resilient, secure, super fast and extremely efficient access
to network services to over 153 countries across the world. All without
having to leave the Cable&Wireless Worldwide network.

The company's Multi-Service Platform, an IP-based
next-generation platform that operates across the NGN, offers a single
environment on which voice and data applications can be converged to drive
business efficiencies.

To find out more, visit www.cw.com

    Media Contacts:
    Hotwire
    Claire Lorimer
    Claire.lorimer@hotwirepr.com
    +44-(0)20-7608-4667

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