UK Oil and Gas Investments, the company that claimed last week it had discovered 100bn barrels of oil in the Weald, announced this morning it doesn’t actually know how much oil there is.

UKOG released a clarification within the past two hours following press reports about its oil find at Horse Hill near Horley in Surrey. It said:

“The OIP [oil in place] hydrocarbon volumes estimated should not be considered as either contingent or prospective resources or reserves.

“Further development work in the form of appraisal drilling, well testing and assessment of recovery factors will be required to seek to quantify net resources in relation to the Company’s licence areas and to prove its commerciality.”

On 9^th April, in a regulatory statement, UKOG said it had made a “significant discovery” at Horse Hill. Our report It estimated there were 158m barrels per square mile, based on analysis by the US firm Nutech Ltd. The statement didn’t estimate a total volume for the Weald, but the chief executive, Stephen Sanderson, said in media interviews there were potentially up to 100 billion barrels of oil.

He said:

“Based on what we’ve found here, we’re looking at between 50 and 100 billion barrels of oil in place in the ground. We believe we can recover between 5% and 15% of the oil in the ground, which by 2030 could mean that we produce 10%-to-30% of the UK’s oil demand from within the Weald area,”

UKOG has an interest in PEDL 137, which covers 55 sq miles of the Weald Basin. This morning, the company admitted it “not undertaken work outside of its licence areas sufficient to comment on the possible OIP in either the approximate 1,100 square miles or the whole of the Weald Basin.” It added:

“In order to establish estimates of total OIP within the licence areas, the semi-regional resource potential of the Weald Basin’s eastern footprint is the subject of ongoing analysis under the contracted alliance between Nutech, UKOG and Solo Oil Plc. The results of the estimated OIP within the licence will be reported when completed.”

Immediately after last week’s announcement, UKOG shares rose more than 200%. They have since dropped back and at the time of writing stand at 2.32p.

Brenda Pollack, of Friends of the Earth, responded to this morning’s announcement: “UKOG has backtracked on the wild claims it made last week and admitted that it has no idea how much oil is under the Sussex Weald. This is yet another example of the potential for shale oil and gas being overhyped by an industry desperate to start pumping profits with little concern for residents or the climate. We need to leave fossil fuels in the ground and invest in the real alternative of renewables and cutting energy waste if we are serious about avoiding the worst impacts of climate change.”

[Updated at 22.10 on 15//4/15 to include Friends of the Earth quote]