Hague and London Oil Regulatory News (HNL)

19 March 2012

WESSEX EXPLORATION PLC

(AIM: WSX)

Rule 2.10 announcement

In accordance with Rule 2.10 of the Code, Wessex Exploration plc announces that, as of the date of the announcement, it has in issue 719,364,824 ordinary shares of 0.1 pence each. These shares are traded on the AIM market of the London Stock Exchange. The International Securities Identification Number ("ISIN") number of the ordinary shares is GB00B4MVKX18

Dealing Disclosure Requirements

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 Disclosure 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 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. You should contact the Panel's Market Surveillance Unit on +44 (0)20 7638 0129 if you are in any doubt as to whether you are required to make an Opening Position Disclosure or a Dealing Disclosure.

WH Ireland, which is authorised and regulated in the United Kingdom by the Financial Services Authority, is acting exclusively for Wessex and for no one else in connection with the possible offer and will not be responsible to anyone other than Wessex for providing the protections afforded to clients of WH Irelandnor for providing advice in relation to the possible offer or any other matters referred to in this announcement.

A copy of this announcement will be available on the website of the Company at www.wessexexploration.com