Hague and London Oil Regulatory News (HNL)

WESSEX EXPLORATION PLC

(AIM: WSX)

Guyane Update

Wessex Exploration PLC ("Wessex" or "the Company") announces plans to commence drilling in mid 2012 on the Guyane permit, to follow up on the Zaedyus oil discovery in late 2011 that demonstrated the prospectivity of this licence area off South America.

In the Zaedyus exploration well, 72 metres of net oil pay was discovered in two turbidite sand systems in the first phase of drilling - successfully proving that the Jubilee play is mirrored across the Atlantic from West Africa.

The second phase of drilling is planned to involve the spudding of a de-lineation well on the discovery, likely to be followed by an exploration well on one of the neighbouring prospects within the area captured by 3D seismic survey. Additional 3D seismic is also planned to be acquired from midyear to further delineate leads on trend and similar to the Zaedyus discovery mapped on 2D seismic along the length of the deepwater margin.

To undertake these operations Shell, who took over as Operator from Tullow Oil on 1 February 2012, has contracted the Stena DrillMax ICE drill-ship, which is expected to commence operations midyear subject to government consents.

Shell (45%) operates the Guyane Maritime permit and is partnered by Total (27.5%), Total (25%) and Northpet (2.5%), a company owned 50% by Northern Petroleum plc and 50% by Wessex Exploration.

Frederik Dekker, Managing Director of Wessex stated, "We are pleased that the successful Zaedyus oil discovery is to be quickly followed by a new drilling campaign. Wessex looks forward to being part of an extremely professional and well-managed operation in French Guiana"

This announcement has been approved by Frederik Dekker, BSc. (Geology), MA (Geology) FGS, who is a registered professional geologist with the American Association of Petroleum Geologist (AAPG). Mr Dekker is the Managing Director of Wessex Exploration and has over 40 years of experience in the oil industry.

Rule 2.10 Requirement

In accordance with Rule 2.10 of the Code, Wessex confirms that as at the date of this announcement it has in issue 721,364,824 ordinary shares of 0.1 pence each. 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 Ireland nor 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