The Merger Agreement and the above description have been
included to provide investors and security holders with
information regarding the terms of the Merger Agreement. They
are not intended to provide any other factual information about
the Company, Atwood or their respective subsidiaries or
affiliates or equity holders. The representations, warranties
and covenants contained in the Merger Agreement were made only
for purposes of those agreements and as of specific dates, were
solely for the benefit of the parties to the Merger Agreement
and may be subject to limitations agreed upon by the parties,
including being qualified by confidential disclosures made by
each contracting party to the other for the purposes of
allocating contractual risk between them that differ from those
applicable to investors. Investors should be aware that the
representations, warranties and covenants or any description
thereof may not reflect the actual state of facts or condition
of the Company, Merger Sub, Atwood or any of their respective
subsidiaries, affiliates, businesses, or equity holders.
Moreover, information concerning the subject matter of the
representations, warranties and covenants may change after the
date of the Merger Agreement, which subsequent information may
or may not be fully reflected in public disclosures by the
Company or Atwood. Accordingly, investors should read the
representations and warranties in the Merger Agreement not in
isolation but only in conjunction with the other information
about the Company or Atwood and their respective subsidiaries
that the respective companies include in reports, statements
and other filings they make with the U.S. Securities and
Exchange Commission (the SEC).

Item8.01 Other Events.

In connection with the announcement of the Merger, the Company
sent certain written communication to its employees and
customers, which are filed as Exhibit99.1 and Exhibit99.2,
respectively.

Item9.01 Financial Statements and
Exhibits.

(d)Exhibits

* Certain schedules have been omitted to Item601(b)(2)of
Regulation S-K. A copy of any omitted schedule will be
furnished to the SEC upon request.

* * *

Additional Information and Where You Can Find
It

This communication does not constitute an offer to sell
or the solicitation of an offer to buy any securities or a
solicitation of any vote or approval. The proposed merger
between the Company and Atwood will be submitted to the
respective shareholders of the Company and Atwood for their
consideration.

In connection with the proposed merger, the Company will file a
registration statement on FormS-4, including a joint proxy
statement/prospectus of the Company and Atwood, with the SEC.
INVESTORS AND SECURITY HOLDERS OF THE COMPANY AND ATWOOD ARE
ADVISED TO CAREFULLY READ THE REGISTRATION STATEMENT AND PROXY
STATEMENT/PROSPECTUS (INCLUDING ALL AMENDMENTS AND SUPPLEMENTS
THERETO) WHEN THEY BECOME AVAILABLE BECAUSE THEY WILL CONTAIN
IMPORTANT INFORMATION ABOUT THE MERGER, THE PARTIES TO THE
MERGER AND THE RISKS ASSOCIATED WITH THE MERGER. A definitive
joint proxy statement/prospectus will be sent to security
holders of the Company and Atwood seeking their approval of the
proposed merger connection with the Company and Atwood
shareholder meetings. Investors and security holders may obtain
a free copy of the joint proxy statement/prospectus (when
available) and other relevant documents filed by the Company
and Atwood with the SEC from the SECs website at www.sec.gov.
Security holders and other interested parties will also be able
to obtain, without charge, a copy of the joint proxy
statement/prospectus and other relevant documents (when
available) by directing a request by mail or telephone to
either Investor Relations, Ensco plc,

5847 San Felipe, Suite3300, Houston, Texas 77057, telephone
713-430-4607, or Investor Relations, Atwood Oceanics,Inc.,
15011 Katy Freeway, Suite800, Houston, Texas 77094, telephone
281-749-7840. Copies of the documents filed by the Company with
the SEC will be available free of charge on Enscos website at
www.enscoplc.com under the tab Investors. Copies of the
documents filed by Atwood with the SEC will be available free
of charge on Atwoods website at www.atwd.com under the tab
Investor Relations. Security holders may also read and copy any
reports, statements and other information filed with the SEC at
the SEC public reference room at 100 F Street N.E., Room 1580,
Washington, D.C. 20549. Please call the SEC at (800) 732-0330
or visit the SECs website for further information on its public
reference room.

Participants in the Solicitation

The Company and Atwood and their respective directors,
executive officers and certain other members of management may
be deemed to be participants in the solicitation of proxies
from their respective security holders with respect to the
transaction. Information about these persons is set forth in
the Companys proxy statement relating to its 2017 General
Meeting of Shareholders and Atwoods proxy statement relating to
its 2017 Annual Meeting of Shareholders, as filed with the SEC
on March31, 2017 and January9, 2017, respectively, and
subsequent statements of changes in beneficial ownership on
file with the SEC. Security holders and investors may obtain
additional information regarding the interests of such persons,
which may be different than those of the respective companies
security holders generally, by reading the joint proxy
statement/prospectus and other relevant documents regarding the
transaction, which will be filed with the SEC.

Cautionary Note Regarding Forward-Looking
Statements

Statements included in this communication regarding the Company
and Atwood and the proposed merger and statements that are not
historical facts are forward-looking statements (including
within the meaning of Section21E of the Securities Exchange Act
of 1934, as amended, and Section27A of the Securities Act of
1933, as amended). Forward-looking statements include words or
phrases such as anticipate, believe, contemplate, estimate,
expect, intend, plan, project, could, may, might, should, will
and words and phrases of similar import. These statements
involve risks and uncertainties including, but not limited to,
actions by regulatory authorities, rating agencies or other
third parties, actions by the respective companies security
holders, costs and difficulties related to integration of
Atwood, delays, costs and difficulties related to the
transaction, market conditions and the Companys financial
results and performance following the completion of the merger,
satisfaction of closing conditions, ability to repay debt and
timing thereof, availability and terms of any financing and
other factors detailed in the risk factors section and
elsewhere in the Companys and Atwoods Annual Report on Form10-K
for the year ended December31, 2016 and September30, 2016,
respectively, and their respective other filings with the SEC,
which are available on the SECs website at www.sec.gov. Should
one or more of these risks or uncertainties materialize (or the
other consequences of such a development worsen), or should
underlying assumptions prove incorrect, actual outcomes may
vary materially from those forecasted or expected. All
information in this document is as of today. Except as required
by law, both the Company and Atwood disclaim any intention or
obligation to update publicly or revise such statements,
whether as a result of new information, future events or
otherwise.

No Offer or Solicitation

This communication is not intended to and does not constitute
an offer to sell or the solicitation of an offer to subscribe
for or buy or an invitation to purchase or subscribe for any
securities or the solicitation of any vote in any jurisdiction
to the proposed transaction or otherwise, nor shall there be
any sale, issuance or transfer of securities in any
jurisdiction in contravention of applicable law. Subject to
certain exceptions to be approved by the relevant regulators or
certain facts to be ascertained, the public offer will not be
made directly or indirectly, in or into any jurisdiction where
to do so would constitute a violation of the laws of such
jurisdiction, or by use of the mails or by any means or
instrumentality (including without limitation, facsimile
transmission, telephone and the internet) of interstate or
foreign commerce, or any facility of a national securities
exchange, of any such jurisdiction.

Service of Process

The Company is incorporated under the laws of England and
Wales. In addition, some of its officers and directors reside
outside the United States, and some or all of its assets are or
may be located in jurisdictions outside the United States.
Therefore, investors may have difficulty effecting service of
process within the United States upon those persons or
recovering against the Company or its officers or directors on
judgments of United States courts, including judgments based
upon the civil liability provisions of the United States
federal securities laws. It may not be possible to sue the
Company or its officers or directors in a non-U.S. court for
violations of the U.S. securities laws.

to the requirements of the Securities Exchange Act of 1934, the
registrant has duly caused this report to be signed on its
behalf by the undersigned hereunto duly authorized.

EXHIBITINDEX

* Certain schedules have been omitted