Costain Regulatory News (COST)

Costain Group PLC

("Costain" or the "Group")

No intention to make an offer for Mouchel Group plc ("Mouchel")

On 17 February 2011, following the completion of comprehensive initial due diligence, including extensive meetings with management, the Board of Costain submitted a revised, fully deliverable, proposal to the Board of Mouchel comprising 22.25p in cash and 0.5531 new Costain shares for each Mouchel share which, based on Costain's share price of 256.75p as at the close of business on 1 April 2011 (being the last business day prior to this announcement), valued each Mouchel share at 164.26p. The Board of Costain believes that this revised proposal did not carry any significant execution risk.

Following the announcement by Mouchel on 29 March 2011, the Board of Costain offered to undertake a one week period of further due diligence to reconfirm the terms of its revised proposal ahead of the remaining standard transaction implementation steps. This offer has been rejected and, having considered its options, the Board of Costain has therefore decided to withdraw its revised proposal and confirms that Costain has no intention of making an offer for Mouchel.

Through the Group's "Choosing Costain" strategy, Costain is making good progress in achieving its vision to be one of the UK's top solutions providers, with the scale and capability to meet successfully the increasingly complex and challenging needs of major customers. Costain's growth aspirations and ambition for the business will be achieved by a combination of organic growth and suitable acquisitions in line with strategy.

For the purposes of Rule 2.8 of the City Code, Costain reserves the right to announce an offer or possible offer or make or participate in an offer or possible offer for Mouchel (and/or take any other action which would otherwise be restricted under Rule 2.8 of the City Code) within the next six months following the date of this announcement:

(i) with the agreement or recommendation of the Board of Mouchel;

(ii) following the announcement by or on behalf of a third party of a firm intention to make an offer for Mouchel or following the announcement of a possible offer for Mouchel;

(iii) following the announcement by Mouchel of a "whitewash" proposal or a reverse takeover; or

(iv) if there is a material change of circumstances.

Enquiries:

A copy of this announcement will shortly be available, free of charge, on the Group's website at www.costain.com

Investec (which is authorised and regulated in the United Kingdom by the Financial Services Authority) is acting exclusively for Costain and for no one else in connection with the possible offer and will not be responsible to anyone other than Costain for providing the protections afforded to Investec clients nor for providing advice in relation to the possible offer or any other matters referred to in this announcement.

This announcement does not constitute an offer to purchase any securities, or an offer to sell or the solicitation of an offer to buy any securities, nor shall there be any offer to purchase or sell securities in any jurisdiction in which such offer, solicitation or sale would be unlawful. No offering of securities may be made in the United States except pursuant to registration under the US Securities Act of 1933 or an exemption from registration.

The release, distribution or publication of this announcement in jurisdictions other than the UK may be restricted by law and therefore any persons who are subject to the laws of any jurisdiction other than the UK should inform themselves about and observe any applicable requirements. If you are resident outside the UK, you are responsible for first satisfying yourself as to the full observance of the laws and regulatory requirements of your jurisdiction.

Unless otherwise determined by Costain, this announcement and any proposed offer will not be made, directly or indirectly, in or into any jurisdiction where to do so would violate the laws of that jurisdiction (a "Restricted Jurisdiction") or the United States, or by the use of any means or instrumentally (including, without limitation, telex, facsimile transmission, telephone, internet or other forms of electronic communication) of interstate or foreign commerce, or of any facility of a national securities exchange of any Restricted Jurisdiction or the United States. Unless so determined by Costain, the proposed offer will not be capable of acceptance by any such use, means or instrumentally or facility of any Restricted Jurisdiction or the United States.

Copies of this announcement and documents relating to any offer will not be, and must not be, directly or indirectly, mailed or otherwise forwarded (including, without limitation, by telex, facsimile transmission, telephone, internet or other forms of electronic communication), distributed or sent in, into or from any Restricted Jurisdiction or the United States.

Forward looking statements

This announcement contains statements about Costain that are or may be forward looking statements. All statements other than statements of historical facts included in this announcement may be forward looking statements. Without limitation, any statements preceded or followed by or that include the words "targets", "plans" "believes", "expects", "aims", "intends", "will", "may", "anticipates", "estimates", "projects" or words or terms of similar substance or the negative thereof, are forward looking statements.

Such forward looking statements involve risks and uncertainties that could significantly affect expected results and are based on certain key assumptions. Many factors could cause actual results to differ materially from those projected or implied in any forward looking statements. Due to such uncertainties and risks, readers are cautioned not to place undue reliance on such forward looking statements, which speak only as of the date hereof. Costain disclaims any obligation to update any forward looking or other statements contained herein, except as required by applicable law.