Press Release

| October 11, 2011

Dewey & LeBoeuf Represents EnCore Oil plc on its Recommended £221 Million Takeover by Premier Oil plc

(LONDON – October 11, 2011) – Dewey & LeBoeuf is acting for UK-based oil and gas exploration and production company EnCore Oil plc in its recommended £221 million ($340 million) acquisition by Premier Oil plc. The acquisition will be effected by a Court approved Scheme of Arrangement. Premier is offering 70 pence per EnCore share in cash and EnCore shareholders can elect to receive 0.2067 new Premier shares for each EnCore share held instead of part or all of the cash consideration.

The consideration represents a premium of approximately 55 percent to the closing price of EnCore shares the day before announcement.

The Dewey & LeBoeuf team is being led by partner James Lewis and includes associates Kirsten Rodger and Jonathan Woodall and legal assistant Abidemi Akinola.

This memorandum is intended only as a general discussion of these issues. It is not considered to be legal advice. We would be pleased to provide additional details or advice about specific situations. For additional information on this important topic, please feel free to call upon your Dewey & LeBoeuf relationship partner. No part of this publication may be reproduced, in whole or in part, in any form, without our prior written consent. For further information on Dewey & LeBoeuf, please visit www.dl.com. +1 888 532 6383