Augean : Shareholder – 28 May 2021

28 May 2021

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 OF SUCH JURISDICTION.

THIS LETTER IS IMPORTANT AND REQUIRES YOUR IMMEDIATE ATTENTION.

If you are in any doubt about the action you should take, you are recommended to seek your own financial advice from your broker, bank manager, solicitor, accountant or other independent financial adviser duly authorised under the Financial Services and Markets Act 2000 if you are in the United Kingdom or, if not, from another appropriately authorised independent financial adviser.

If you have sold or otherwise transferred all of your shares in Augean plc, please send this letter and the accompanying document at once to the purchaser or transferee or to the broker, bank or other agent through whom the sale or transfer was effected for transmission to the purchaser or the transferee. However, such documents should not be forwarded or transmitted in or into any jurisdiction where to do so would constitute a violation of the relevant laws or regulations of such jurisdiction.

Augean plc

(Incorporated in England and Wales under the Companies Act 1985, No. 05199719) Registered office:

4 Rudgate Court

Walton, Wetherby

West Yorkshire

LS23 7BF

To: The shareholders of Augean plc (the "Company") d persons with information rights
	"Announcement"		Stanley	Infrastructure Inc. (	"MSI"	) made an
As you may be aware, on 27 May 2021, Morgan
announcement (the		), in response to press speculation, that it is in the preliminary

			"Proposal"
stages of considering making an approach to the Company regarding a possible offer for the entire
issued and to be issued share capital of the Company (the		).
		"Company Announcement"
In accordance with Rule 2.11 of the Code, I enclose a copy of the Announcement issued by MSI and the
"Announcements"					, and together the
Company's response to the Announcement (the
	) to keep you informed of developments. The Announcements include a summary of
the provisions of Rule 8 of the Code.

Although the Announcement has put the Company into an 'offer period' under the Takeover Code, there can be no certainty that a firm offer will be made, nor as to the terms on which any firm offer might be made. If an announcement of a firm intention to make an offer is made, the formal offer documentation providing further information about the offer will be made available to you in due course. In the meantime, you do not need to take any action.

This letter is not a summary of the information in the Announcements and should not be taken as a summary of the information in the Announcements and should not be regarded as a substitute for reading the Announcements in full. A copy of this letter and the Announcements have been published on the Company's website at https:// https://www.augeanplc.com/offer/. For the avoidance of doubt, the content of this website is not incorporated into, and does not form part of, this letter.

Please be aware that addresses, electronic addresses and certain other information provided by you for the receipt of communications from the Company may be provided to MSI or any other potential bidder during the offer period as required under Section 4 of Appendix 4 of the Code.

If you have any questions about this letter, the Announcements or any administrative issue, please contact the Company's registrars, Computershare Investor Services PLC during business hours on 0370 889 3205 (or if calling from outside the UK [phone]) or by submitting a request in writing at PO Box 82, The Pavilions, Bridgwater Road, Bristol, BS99 6ZZ.

You may request a hard copy of the Announcement. You may request that all future documents, announcements and information in relation to the Proposal be sent to you in hard copy form and subsequently such information will be sent to you in hard copy without the need to make any further requests. Such requests may be made to Computershare Investor Services PLC in writing to the address set out above or by calling the telephone number above.

Yours sincerely

Jim Meredith

Executive Chairman

Augean plc

N.M. Rothschild & Sons Limited (), which is authorised and regulated in the United Kingdom by the Financial Conduct"RothschildAuthority, is&actingCo" exclusively for the Company and no one else in connection with the matters referred to in this letter and will not be responsible to anyone other than the Company for providing the protections afforded to its clients or for giving advice in relation to such matters.

4 Rudgate Court | Walton | Near Wetherby | West Yorkshire | LS23 7BF

Tel [phone]

www.augeanplc.com

Augean plc. Incorporated in England and Wales. Registered Number: 5199719