Acquisition of shares

NOT FOR RELEASE, PUBLICATION OR DISTRIBUTION IN WHOLE OR IN PART IN, INTO OR FROM ANY JURISDICTION WHERE TO DO SO WOULD CONSTITUTE A VIOLATION OF THE RELEVANT LAWS OR REGULATIONS OF THAT JURISDICTION

FOR IMMEDIATE RELEASE

28 June 2010

CH2M HILL Companies, Ltd ("CH2M HILL"): Acquisition of shares in Scott Wilson Group plc ("Scott Wilson")

Further to its earlier announcement, CH2M HILL confirms that it has acquired 9,544,277 ordinary shares of Scott Wilson (representing 12.97% of the issued share capital of Scott Wilson) at a price of 245 pence per share.

Enquiries

Contacts:

CH2M HILL Jacqueline Rast +44 (0) 207 404 5959

Rothschild: Paul Simpson +44 (0)121 600 5252

(Financial adviser) Stuart Vincent +44 (0) 207 280 5436

Investec: Keith Anderson +44(0)2075975110 (Corporate broker) Charlie Batten +44 (0) 207 597 5184

Brunswick: Kate Holgate +44 (0) 207 404 5959

Jayne Rosefield +44 (0) 207 404 5959

A copy of this announcement will be available at www.ch2m.com

Disclosure requirements of the Takeover Code (the "Code")

Under Rule 8.3(a) of the Code, any person who is interested in 1% or more of any class of relevant securities of an offeree company or of any paper offeror (being any offeror other than

an offeror in respect of which it has been announced that its offer is, or is likely to be, solely in cash) must make an Opening Position Disclosure following the commencement of the offer

period and, if later, following the announcement in which any paper offeror is first identified.

An Opening Position Disclosure must contain details of the person's interests and short

positions in, and rights to subscribe for, any relevant securities of each of (i) the offeree

company and (ii) any paper offeror(s). An Opening Position Disclosure by a person to whom

Rule 8.3(a) applies must be made by no later than 3.30 pm (London time) on the 10th

business day following the commencement of the offer period and, if appropriate, by no later

than 3.30 pm (London time) on the 10th business day following the announcement in which

any paper offeror is first identified. Relevant persons who deal in the relevant securities of the

offeree company or of a paper offeror prior to the deadline for making an Opening Position

Disclosure must instead make a Dealing Disclosure.

Under Rule 8.3(b) of the Code, any person who is, or becomes, interested in 1% or more of

any class of relevant securities of the offeree company or of any paper offeror must make a

Dealing Disclosure if the person deals in any relevant securities of the offeree company or of

any paper offeror. A Dealing Disclosure must contain details of the dealing concerned and of

the person's interests and short positions in, and rights to subscribe for, any relevant

securities of each of (i) the offeree company and (ii) any paper offeror, save to the extent that

these details have previously been disclosed under Rule 8. A Dealing Disclosure by a person

to whom Rule 8.3(b) applies must be made by no later than 3.30 pm (London time) on the

business day following the date of the relevant dealing.

If two or more persons act together pursuant to an agreement or understanding, whether

formal or informal, to acquire or control an interest in relevant securities of an offeree

company or a paper offeror, they will be deemed to be a single person for the purpose of Rule

8.3.

Opening Position Disclosures must also be made by the offeree company and by any offeror

and Dealing Disclosures must also be made by the offeree company, by any offeror and by

any persons acting in concert with any of them (see Rules 8.1, 8.2 and 8.4).

Details of the offeree and offeror companies in respect of whose relevant securities Opening

Position Disclosures and Dealing Disclosures must be made can be found in the Disclosure

Table on the Takeover Panel's website at www.thetakeoverpanel.org.uk, including details of

the number of relevant securities in issue, when the offer period commenced and when any

offeror was first identified. If you are in any doubt as to whether you are required to make an

Opening Position Disclosure or a Dealing Disclosure, you should contact the Panel's Market

Surveillance Unit on +44 (0)20 7638 0129.