Larne Project Update

Portland Gas plc
31 March 2008


For Immediate Release                                              31 March 2008


                                  Portland Gas

                                 PRESS RELEASE


                Results of the 3D seismic survey - Larne project


The Directors of Portland Gas plc (AIM: PTG) ('the Company' or 'Portland Gas')
are pleased to announce the results of the 3D seismic programme acquired during
October and November 2007 by its wholly owned Northern Ireland subsidiary
Portland Gas NI Limited.

The interpretation of the data has indicated that the Permian salt sequence
encountered in 1981 in the Larne-2 borehole extends as anticipated under Larne
Lough into the area where Portland Gas was granted an exploration licence in
2007 by The Crown Estate. Interpretation of the seismic data indicates that the
salt in the target area is at a depth of approximately 1400 metres with a
thickness of approximately 200 meters. Portland Gas is now planning to drill a
borehole later in 2008 on Islandmagee to confirm the seismic interpretation and
to take cores of the salt sequence to complete the design of the caverns to
store natural gas. The Company is seeking a suitable site from which to drill
the borehole within the area of its onshore mineral licence, awarded in 2007
near Ballylumford by the Department of Enterprise, Trade and Investment.

The Company is also negotiating terms with a strategic partner to take a 25-35%
interest in the project. Portland Gas will be the operator of the proposed joint
venture.

Portland Gas is now undertaking an Environmental Impact Assessment with the
intention of submitting a full planning application for the gas storage project
in 2009, subject to concluding any necessary landowner agreements. The Company
will liaise closely during 2008 with all stakeholders to ensure that the surface
facilities, required to create the caverns and compress the gas into store, are
located in the most appropriate place and designed to minimise visual and
environmental impact. The caverns would be created within the salt sequence
below Larne Lough but accessed from directionally drilled boreholes on the land.
The nearest point of connection to the national gas infrastructure is at the
Scotland to Northern Ireland Pipeline above ground installation at Ballylumford.

Network, market, technical and economic analyses are also underway to determine
the most appropriate storage capacity and the gas injection and withdrawal rates
for the facility. Initial studies indicate that the facility could have a
storage volume of up to 500 million cubic metres (18 billion cubic feet) of gas.
In this case some reinforcement of the current gas infrastructure will be
required to manage the injection and withdrawal of gas and provide sufficient
flexibility to meet demand spikes for customers.

Portland Gas would ensure that the capacity availability is Third Party Access
compliant under Northern Ireland and European legislation. It is anticipated
that a proportion of the capacity in the facility would be made available under
long-term contracts to facilitate the debt financing of the project, however the
majority would be auctioned on an annual basis. Customers could be based in
Northern Ireland, the remainder of the UK or the Republic of Ireland.


Commenting on the project Andrew Hindle, the CEO of Portland Gas plc, said:

'We are delighted with the results of the seismic programme. The asset would
have a significant positive impact on the dynamics of the gas market in the
whole of Ireland and add significantly to security of gas supplies. Indeed, in
winter, Northern Ireland could become a net exporter of gas from its current
position of 100% dependence on imports.'



For further information please contact:


Portland Gas plc
Andrew Hindle, Chief Executive Officer                020 8332 1200
Craig Gouws, Chief Financial Officer

Investor Relations - Buchanan Communications          020 7466 5000
Ben Willey

Corporate PR - Watershed                              01308 420785
Sara Hudston

Jet PR (Northern Ireland Public Relations Consultant) 07803 722322
Jacqui Thompson

Nominated Advisor and Broker - Seymour Pierce         020 7107 8000
Jonathan Wright


Notes to Editors:


Background on Portland Gas plc

Portland's business focuses on the development of gas storage projects in the
United Kingdom and internationally. It currently has two projects in its
portfolio, the first an advanced project at the Isle of Portland which has been
under development for over 3 years, and the second the Larne Lough project in
Northern Ireland which was announced in July 2007. Further information is
available on the Company's website www.portland-gas.com.


Background to gas storage

Natural gas is an extremely important source of energy, currently contributing
37 per cent of the UK's energy needs. For many years, the UK has relied heavily
on the its North Sea gas fields. That resource of secure and sustainable gas
flow has limited the need to provide significant storage volumes since daily and
seasonal demands for gas have been accommodated by the flexibility of supplies
close to shore. This relative luxury is becoming less and less sustainable as
the UK becomes increasingly reliant on less flexible imported gas, the outcome
of which is that in order to maintain control of supply and demand requirements,
the need for a substantial portfolio of natural gas storage facilities is now a
national issue.

Gas storage plays an important role in managing swing demand and mitigating the
need for (expensive) emergency imports. Gas storage facilities can be filled
during times of lower demand to be available during periods of higher demand,
either on a daily basis or seasonally.

Opportunities for a safe and environmentally friendly method of storing gas are
relatively few. One of the safest and most environmentally friendly methods of
storing large quantities of gas is deep underground within caverns created
within salt sequences.




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