Plectrum Petroleum

Cairn Energy PLC
18 September 2007


Not for release, publication or distribution, in whole or in part, in or into or
from the United States, Canada, Australia, Japan or any jurisdiction where to do
   so would constitute a violation of the relevant laws of such jurisdiction

Capricorn Oil & Gas Limited (a subsidiary of Cairn Energy PLC) ('Capricorn')
recommended offer for Plectrum Petroleum Plc ('Plectrum Petroleum'):
notification of posting of the Offer Document.

Further to the announcement made on 7 September 2007 of a recommended cash offer
by Capricorn for the entire issued and to be issued share capital of Plectrum
Petroleum, Capricorn announces that the Offer Document containing the full terms
of, and conditions to, the Offer is today being posted to Plectrum Petroleum
Shareholders, together with the Form of Acceptance (in the case Plectrum
Petroleum Shareholders who hold Plectrum Petroleum Shares in certificated form).

Copies of the Offer Document and the Form of Acceptance are available for
inspection (during normal business hours only) at the offices of Shepherd and
Wedderburn LLP at Condor House, 10 St Paul's Churchyard, London EC4M 8AL and
collection (during normal business hours only) from Lloyds TSB Registrars,
Princess House, 1 Suffolk Lane, London EC4R 0AX throughout the period during
which the Offer remains open for acceptance.

Terms defined in the Offer Document have the same meaning in this announcement.


ENQUIRIES

For further information contact:

Cairn/Capricorn
Mike Watts                                            0131 475 3000
Simon Thomson

Jefferies International
Richard Kent                                          020 7618 3713

Jefferies International, which is authorised and regulated in the United Kingdom
by the Financial Services Authority, is acting as financial adviser to Cairn and
Capricorn in connection with the Offer and no-one else and will not be
responsible to anyone other than Cairn and Capricorn for providing the
protections afforded to customers of Jefferies International or for providing
advice in relation to the Offer.


                      This information is provided by RNS
            The company news service from the London Stock Exchange