Flow-testing has started at the project in Gatwick.
Chairman of UK Oil & Gas – which owns 32% – Stephen Sanderson said: “UK Oil & Gas remains confident that the comprehensive long-term production testing campaign will provide the necessary data to fully assess Horse Hill’s Portland and Kimmeridge commerciality and help move the project towards timely production and positive cash flow.”
UK Oil & Gas shares were trading 6.6% higher. Other firms with an interest in the project also saw their shares rise.
Alba Minerals was trading up 6.8% and Solo Oil PLC (LON:SOLO) shares gained 2%.