Falkland Oil and Gas (FOGL) (>> Falkland Oil and Gas Limited), Premier Oil (>> Premier Oil PLC) and Rockhopper (>> Rockhopper Exploration Plc) said they had discovered oil in the Isobel Deep exploration well, in the North Falkland Basin, with more work due to be carried out.

"Further operations on the well will be performed," said the FOGL Chief Executive Tim Bushell.

"These could include either a side-track from the existing well or a re-drill of the well near to the current location, depending on what is deemed appropriate once the drilling results have been further evaluated," he said.

In April, Premier Oil and FOGL said they had made an oil and gas discovery at a well in the Falkland Islands, the first after nine months of drilling.

Later that month Argentina launched a lawsuit against the pair, Rockhopper and two further operators in a move which was denounced by Britain as bullying.

FOGL and Rockhopper resumed drilling at the Isobel Deep well this month following the repair of a blow-out prevent control system.

(Reporting by Costas Pitas; editing by Jason Neely)