Guyane Update

WESSEX EXPLORATION PLC

(AIM: WSX)

Guyane Update

Wessex Exploration PLC ("Wessex" or "the Company") notes the Trading Statement and Operational Update of Tullow Oil PLC ("Tullow") made today in respect of progress on the Guyane Maritime block, in which Wessex holds an effective 1.25 per cent. interest. It included the following statement on Guyane.

"French Guiana

In early September 2011, Tullow announced that the Zaedyus exploration well offshore French Guiana made a significant oil discovery. This proved the extension of the Jubilee play across the Atlantic and opened up a new oil basin.

Drilling operations continued until mid-November 2011 with an extensive data gathering programme being conducted including sidetracking of the well in order to cut a core. A liner was run over the main oil bearing reservoir and the well was suspended for future re-entry. The rig went off contract on 23 November 2011. Core studies are currently underway and the initial phase will be completed in early-2012.

The Joint Venture partners are discussing a comprehensive follow-up exploration and appraisal programme which will include 3D seismic acquisition and a drilling programme, scheduled to commence in mid-2012.

The Ministerial Order granting Tullow, Shell and Total approval for both the transfer and renewal of the Guyane Maritime permit is expected to be published shortly."

Notes

Partners in the Guyane Maritime permit are Tullow Oil plc ("Tullow") the operator (27.5%), Shell E&P France ("Shell") (45%), Total E&P Guyane Francaise SAS ("Total") (25%) and Northpet Investments Limited (2.5%), a joint venture between Northern Petroleum Plc and Wessex Exploration PLC, each with a beneficial net holding of 1.25%.