Horse Hill Licence Extensions, UK Weald Basin

13 May 2015 Doriemus plc ("Doriemus" or the "Company") Horse Hill Licence Extensions, UK Weald Basin The Board of Dorimeus plc (AIM: DOR) is pleased to announce that it has beeninformed by Horse Hill Developments Ltd ("HHDL") that the exploration stage ofthe Horse Hill ("HH") PEDL137 licence, in which the Company has netattributable interest of 6.5%, has been extended for a further year by the Oil& Gas Authority ("OGA", formerly the Department of Energy and Climate Change).The exploration stage of the PEDL137 licence has been extended to 30 September2016. Subject to the results of an intended Horse Hill-1 ("HH-1") flow test later in2015, for which regulatory approval is required, the Company is informed thatHHDL would seek, in conjunction with the OGA and other regulators, to move thePEDL137 licence into the Production Period, via, inter alia, the submission ofa HH Field Development Plan ("FDP") to the OGA. The PEDL137 licence providesfor a potential Production Period of 19 years. HHDL has informed the Companythat its application for the flow test is based on the roadmap documentpublished by the Department of Energy and Climate Change (now the OGA) foronshore oil and gas exploration in the UK. Dorimeus' interest in Horse Hill: The Horse Hill-1 well is located within onshore exploration License PEDL137, onthe northern side of the Weald Basin near Gatwick Airport. Doriemus owns a 10%direct interest in Horse Hill Developments Ltd. HHDL is a special purposecompany that owns 65% participating interests and is the operator of licencePEDL137 and the adjacent licence PEDL246 in the UK Weald Basin. The remaining35% participating interests in the PEDL137 and PEDL246 licenses are held byMagellan Petroleum Corporation. Doriemuslicence interests Following the extensions to the exploration stages of PEDL137 and PEDL126, theCompany has interests in the following Horse Hill oil & gas licences: Asset Licence Licence Doriemus' Operator or Area Current Holder Economic Non-Operator (km2) Licence Period Interest Expiry Horse PEDL137 Horse Hill 6.5% Non-Operator 99.29 30 SeptemberHill 1 Developments (HHDL is 2016 Ltd Operator) Horse PEDL246 Horse Hill 6.5% Non-Operator 43.58 30 June 2019Hill 1 Developments (HHDL is Ltd Operator) Notes 1 Exploration licence. UK exploration licences provide for the extension beyondthe exploration stage into a production period, subject to meeting certaincriteria, approval by the relevant authorities and, inter alia, the submissionof an FDP to the OGA. Production Periods are typically for 20 years from grantof approval. For further information please contact: Doriemus plcDonald Strang/Hamish Harris +44 (0) 20 7440 0640 Cairn Financial Advisers LLP:James Caithie / Carolyn Sansom +44 (0) 20 7148 7900 Public Relations:Square 1 Consulting Ltd +44 (0) 20 7929 5599David Bick/Mark Longson